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Anatomic pathology > Skin > Flashcards

Flashcards in Skin Deck (352):
0

Dermatophytosis: The "sandwich sign".

Fungal hyphae between the parakeratotic layer and the overlying orthokeratosis.

1

Vitiligo: Typically spared areas (2).

Scalp and eyelashes.

2

Urticarial vasculitis:

A. Clinical features (3).
B. Duration of urticaria.

A. Recurrent urticaria, arthralgia, abdominal pain.

B. More than 24 hours.

3

Urticarial vasculitis: Histology.

Leukocytoclastic vasculitis without significant fibrin in vascular walls.

4

Urticarial vasculitis: Useful adjunctive laboratory tests (2).

Complement studies (CH50, C1q-binding assays).

DFA: May show vascular deposits of complement, immunoglobulins, or fibrin.

5

Urticarial vasculitis: Clinical associations (3).

Infectious hepatitis.

Infectious mononucleosis.

Autoimmune diseases.

6

Telangiectasia macularis eruptiva perstans: Histologic differences from urticaria (2).

Mast cells rather than eosinophils.

No significant dermal edema.

7

Lichen planus: Microbiological association.

Hepatitis C.

8

Lichen planus: Anatomic predilection of lesions (3).

Flexor surfaces.

Lower back.

Glans penis.

9

Oral lichen planus: Histologic differences from lichen planus of skin (3).

Parakeratosis.

Less epidermal hyperplasia.

Frequent ulceration.

10

Lichenoid drug eruption: Histologic differences from lichen planus (2).

Parakeratosis.

Eosinophils (sometimes).

11

Lichen striatus:

A. Age group.
B. Clinical appearance.

A. Children.

B. Unilateral eruption on extremities, trunk, neck.

12

Lichen striatus: Histologic differences from lichen planus.

Inflammatory infiltrate deep in reticular dermis around hair follicles and sweat glands.

13

Lichen nitidus:

A. Age group.
B. Clinical appearance.

A. Children.

B. Small, flat-topped papules.

14

Lichen nitidus: Histologic differences from lichen planus (4).

"Ball-in-claw" infiltrate.

Focal parakeratosis.

Epidermal atrophy.

Many histiocytes.

15

Lichen planopilaris vs. alopecia areata: Histology (2).

Lichen planopilaris: Infiltrate at base of follicular bulb; scarring.

Alopecia areata: Infiltrate along infundibulum; usually no scarring.

16

Erythema multiforme:

A. Infectious cause.
B. Pharmacological cause.

A. HSV.

B. Sulfonamides.

17

Toxic epidermal necrolysis: Drugs that cause it (3).

Sulfonamides.

β-lactam antibiotics.

NSAIDs.

18

Erythema multiforme: Histological feature of late lesion.

Dermal melanophages.

19

Erythema multiforme: Immunofluorescence.

IgM and C3 in the walls of superficial dermal vessels.

20

Angioedema: Histology.

Extension of the edema into the subcutis.

21

Acute GVHD:

A. Timing.
B. Clinical triad.

A. Within 3 months after transplant.

B. Rash, diarrhea, liver dysfunction.

22

Acute GVHD: Grade I.

Vacuolar change in basement membrane.

23

Acute GVHD: Grade II.

Necrotic keratinocytes, satellite necrosis.

24

Acute GVHD: Grade III.

More widespread necrosis of keratinocytes; separation at dermoepidermal junction.

25

Acute GVHD: Grade IV.

Full-thickness necrosis and loss of epidermis.

26

Chronic GVHD: Early phase.

Lichenoid, resembling lichen planus; satellite necrosis may be seen.

27

Chronic GVHD: Late phase.

Sclerosis, resembling scleroderma, but with epidermal atrophy.

28

Discoid lupus: Histology (4).

Hyperkeratosis with follicular plugging.

Epidermal atrophy.

Basal vacuolar change.

Thickened basement membrane.

29

Verrucous lesions of lupus: Histology (2).

Epidermal hyperplasia, papillomatosis.

30

Tumid lupus: Histology.

Superficial and deep infiltrate that spares epidermis; increased dermal mucin.

31

Lupus panniculitis: Histology.

Lobular panniculitis with hyaline fat necrosis.

32

Subacute and neonatal lupus: Histologic differences from discoid lupus (3).

Subacute and neonatal lupus show

− Prominent changes at the D-E junction.
− Less hyperkeratosis.
− Less inflammation.

33

Cutaneous lupus: Immunofluorescence.

Continuous granular deposition of IgG, IgM, and C3 at the dermoepidermal junction.

34

Cutaneous lupus: How to distinguish from polymorphous light eruption.

PLE: More papillary dermal edema than tumid lupus; no dermal mucin.

35

Cutaneous lupus: Lymphoma that may be in the differential diagnosis.

Subcutaneous panniculitis-like T-cell lymphoma must be distinguished from lupus panniculitis.

36

Lupus band test.

Direct immunofluorescence . . .

Discoid lupus: Positive in lesional skin only.

Systemic lupus: Positive in "normal" skin as well.

37

Anatomic location:

A. Heliotrope rash.
B. Gottron's papules.

A. Eyelids.

B. Knuckles, knees, elbows.

38

Dermatomyositis may resemble which type of cutaneous lupus histologically?

Subacute lupus.

39

Dermatomyositis: Age group.

Children.

Adults aged 45-65.

40

Dermatomyositis: Immunofluorescence.

C5b-C9 around blood vessels.

41

Dermatomyositis: Lupus-band test.

Negative.

42

Id reaction:

A. Synonym.
B. Leading cause.

A. Autoeczematization.

B. Remote dermatophytosis.

43

Spongiotic dermatitis: Changes that indicate chronicity (3).

Epidermal hyperplasia.

Hyperkeratosis.

Papillary dermal fibrosis.

44

Seborrheic dermatitis: Histology (2).

Mild spongiosis.

Parakeratosis at follicular ostia.

45

Pityriasis rosea: Histology (3).

Focal spongiosis.

Mounds of parakeratosis.

Extravasated erythrocytes.

46

Eosinophilic spongiosis: Differential diagnosis (4).

Allergic contact dermatitis.

Bullous pemphigoid, early.

Pemphigus, early.

Incontinentia pigmenti.

47

Incontinentia pigmenti:

A. Inheritance.
B. Epidemiology.

A. X-linked dominant.

B. Mostly females.

48

Histology of incontinentia pigmenti: Vesicular stage (3).

Eosinophilic spongiosis.

Single dyskeratotic keratinocytes.

Whorls of squamous cells.

49

Histology of incontinentia pigmenti: Verrucous stage (4).

Hyperkeratosis.

Papillomatosis.

Dyskeratosis.

Occasional eosinophils.

50

Incontinentia pigmenti: Gene and its location.

IKBKG (a.k.a. NEMO) on Xp28.

51

Histology of incontinentia pigmenti:

A. Hyperpigmented stage.
B. Hypopigmented stage (3).

A. Many melanophages in the upper dermis.

B. Epidermal atrophy, loss of melanin, loss of adnexa.

52

Psoriasis: Anatomic sites (3).

Scalp.

Lumbosacral skin.

Extensor surfaces.

53

Psoriasis: Eponymous collections of neutrophils.

Microabscesses of Munro (stratum corneum).

Spongiform pustules of Kogoj (stratum spinosum).

54

Psoriasis: Appearance of granular layer.

Hypogranulosis underlying areas of parakeratosis.

55

Guttate psoriasis: Histology.

Less epidermal hyperplasia than in classic psoriasis.

56

Psoriatic arthritis:

A. Incidence.
B. Affected joints.

A. 15% of patients with psoriasis.

B. The DIP joints.

57

Psoriasis: Risk factor for severe disease.

AIDS.

58

Pityriasis rubra pilaris: Clinical appearance of fully developed disease.

Orange-red scaly plaques containing islands of normal skin.

59

Pityriasis rubra pilaris:

A. Stratum corneum.
B. Follicles.

A. Horizontal and vertical alternation of orthokeratosis and parakeratosis.

B. Dilatation of infundibula; follicular plugging.

60

Pityriasis rubra pilaris: Histological differences from psoriasis (4).

Thick suprapapillary plates.

Short, thick rete pegs.

Hypergranulosis.

No neutrophils in the parakeratotic layer.

61

Polymorphous light eruption: Typical patient and season.

Young woman, summer.

62

Polymorphous light eruption: Anatomic distribution.

Upper chest, extensor surfaces of arms.

63

Polymorphous light eruption: Histology (3).

Normal or slightly spongiotic epidermis.

Marked papillary dermal edema.

Superficial and deep perivascular lymphocytes.

64

Pityriasis lichenoides: Histology (5).

Parakeratosis and scale-crust.

Spongiosis and necrotic keratinocytes.

Basal vacuolar change.

Papillary dermal edema with extravasated RBCs.

Lymphocytes obscure the DEJ and form superficial and deep perivascular infiltrates.

65

Pityriasis lichenoides et varioliformis acuta, ulceronecrotic variant: Histology.

There may be lymphocytic vasculitis.

66

Pityriasis lichenoides: Distinction from lymphomatoid papulosis.

The latter has atypical, CD30-positive lymphocytes.

67

Fixed drug eruption: Histology (4).

Basal vacuolar change that may progress into bullae.

Necrotic keratinocytes.

Superficial and deep perivascular lymphocytes, neutrophils, eosinophils; sometimes also lichenoid.

Melanophages in the upper dermis.

68

Fixed drug eruption: Distinction from erythema multiforme.

Not always possible, but fixed drug eruption is more likely when there is a deeper infiltrate that includes neutrophils and eosinophils.

69

Fixed drug eruption: Instigators (3).

Sulfa drugs.

Aspirin.

Phenolphthalein.

70

Lymphomatoid papulosis: Infiltrate.

Wedge-shaped and consists of neutrophils, eosinophils, plasma cells, and atypical lymphocytes.

71

Lymphomatoid papulosis: Morphology of atypical lymphocytes.

May resemble the cells of

Mycosis fungoides (cerebriform nuclei).

Hodgkin's lymphoma (Reed-Sternberg cells)

Anaplastic large-cell lymphoma.

72

Lymphomatoid papulosis: Feared outcome.

Progression to anaplastic large-cell lymphoma.

73

Secondary syphilis: Histology (5).

Parakeratosis with neutrophils.

Psoriasiform epidermal hyperplasia.

Focal spongiosis.

Basal vacuolar change.

Lichenoid mononuclear inflammation.

74

Lues maligna: Histology.

Thrombotic endarteritis of deep dermal vessels, leading to ischemic necrosis and ulceration.

75

Sweet's syndrome: Clinical triad.

Fever.

Rash.

Leukocytosis.

76

Sweet's syndrome: Anatomic locations of rash.

Face.

Trunk.

Extremities.

77

Sweet's syndrome: Association (3).

AML or other myeloproliferative neoplasm.

Inflammatory disease.

Solid tumor.

78

Sweet's syndrome: Histology (3).

Dense infiltrate of neutrophils with nuclear dust but without leukocytoclastic vasculitis.

Papillary dermal edema.

Dilated blood vessels with plump endothelial cells and extravasated RBCs.

79

Pyoderma gangrenosum: Associations (4).

Connective-tissue disease.

Hematopoietic malignancy.

Inflammatory bowel disease.

Liver disease.

80

Pyoderma gangrenosum: Inflammation.

Center of lesion: Neutrophils.

Border: Mixed infiltrate.

Periphery: Mononuclear.

81

Pyoderma gangrenosum: Vasculitis.

Secondary vasculitis may arise in the necrotic, neutrophil-rich center.

82

Pyoderma gangrenosum in Crohn's disease.

May contain granulomas.

83

Eosinophilic cellulitis: Clinical presentation.

Red patches evolve into painful plaques; recurrent.

84

Eosinophilic cellulitis: Association with peripheral eosinophilia.

Seen in at least half of cases.

85

Eosinophilic cellulitis: Histology (3).

Dense, diffuse dermal infiltrate of eosinophils, sometimes with

− Flame figures.
− Necrobiosis with palisades of histiocytes.

86

Eosinophilic cellulitis: Possible causes (5).

Insect bites.

Parasites.

Infections.

MPNs.

Drugs.

87

Scabies: Name of mite.

Sarcoptes scabei.

88

Scabies: Most common sites of burrows (3).

Webs between fingers.

Palms.

Male genitals.

89

Xanthogranuloma: How many are congenital?

About 20%.

90

Xanthogranuloma: Constituent cells.

Histiocytes.

Touton giant cells.

Neutrophils, eosinophils, lymphocytes.

91

Xanthogranuloma: Immunohistochemical distinction from Langerhans' cell histiocytosis.

Langerhans' cells express CD1a, S100, and langerin.

92

Reticulohistiocytosis: Clinical forms.

Localized: Limited to skin.

Systemic: Involves skin, heart, bone, joints, lymph nodes.

93

Systemic reticulohistiocytosis: Associations (3).

Hyperlipidemia.

Internal malignancies.

Autoimmune disease.

94

Reticulohistiocytoma: Morphology of defining cell.

Epithelioid histiocyte with abundant, pale-pink, glassy cytoplasm.

95

Granuloma annulare: Typical anatomic sites.

Dorsa of hands and feet, knees, ankles, elbows.

96

Granuloma annulare: Distribution of histiocytes.

Palisaded, interstitial, or a combination of both.

97

Granuloma annulare: Histological distinction from rheumatoid nodule.

Rheumatoid nodule:

- Necrobiosis is more eosinophilic and sometimes fibrinoid; no mucin.
- Subcutaneous location.

98

Granuloma annulare in children.

May be subcutaneous and hence difficult to distinguish from rheumatoid nodule.

99

Rheumatoid nodule: Anatomic sites (2).

PIP joints, MCP joints.

100

Necrobiosis lipoidica: Classic anatomic site.

Shins.

101

Necrobiosis lipoidica: Appearance of necrobiosis.

Basophilic degeneration of collagen.

102

Necrobiosis lipoidica: Relevance to diabetes (2).

Occurs in less than 1% of diabetics.

Occurs at a later age in diabetics than in non-diabetics.

103

Necrobiotic xanthogranuloma:

A. Clinical association.
B. Typical anatomic location.

A. Paraproteinemia.

B. Periorbital skin.

104

Necrobiotic xanthogranuloma: Histology (3).

Foam cells, Touton giant cells, lymphocytes.

Intervening zones of necrobiosis.

Lymphoid follicles sometimes.

105

Lupus pernio:

A. Site of lesions.
B. Clinical significance.

A. Central face.

B. Increased risk of pulmonary sarcoidosis.

106

Löfgren's syndrome: Clinical triad.

Hilar adenopathy, acute polyarthritis, erythema nodosum.

A variant presentation of sarcoidosis.

107

Sarcoidosis: Appearance of granulomas.

Noncaseating; minimal peripheral lymphocytic infiltrate.

108

Sarcoidosis: Appearance of panniculitis.

Lobular pattern; noncaseating granulomas.

109

Foreign substances that can cause sarcoidal granulomas (3).

Silica.

Beryllium.

Zirconium.

110

Inflammatory infiltrate of leprosy:

A. Tuberculoid.
B. Lepromatous.
C. Borderline.

A. Granulomas.

B. Foam cells; few lymphocytes.

C. Foam cells and epithelioid histiocytes in poorly formed granulomas; many lymphocytes.

111

Leprosy: Where to find organisms.

Abundant in lepromatous leprosy; few in tuberculoid leprosy.

Found in histiocytes, nerves, arrectores pilorum.

112

Histoid leprosy.

Histologically resembles a histiocytoma but is full of acid-fast bacilli.

113

Lupus vulgaris: Etiologies (2).

Hematogenous spread to skin from reactivated pulmonary focus of TB.

Lymphatic spread to skin from cervical lymph nodes.

114

Lupus vulgaris:

A. Anatomic site.
B. Clinical course.

A. Central face.

B. Peripheral extension with atrophy and occasional ulceration.

115

Lupus vulgaris: Histology (3).

Tuberculoid granulomas with little or no caseation.

In older lesions, fibrosis replaces granulomas.

Epidermis may be atrophic, ulcerated, or hyperplastic.

116

Lupus vulgaris: Demonstration of bacilli.

Special stains rarely help.

PCR is better.

117

Lupus vulgaris: Complication.

Development of SCC or BCC.

118

Deep mycoses: Typical histology.

Pseudoepitheliomatous hyperplasia with extensive dermal suppurative and granulomatous inflammation.

119

Deep mycoses: Appearance of panniculitis.

Lobular; suppurative and granulomatous.

120

Blastomycosis: Histology of spores (3).

8-15 μm, thick-walled, broad-based budding.

121

Paracoccidiomycosis: Histology of spores (2).

6-20 μm, narrow-based budding.

122

Chromoblastomycosis: Histology of spores (3).

6-12 μm, thick-walled, dark-brown and in clusters ("copper pennies").

123

Cryptococcus: Histology of spores.

2-4 μm (4-12 μm with capsule), narrow-based budding.

124

Histoplasmosis: Histology of spores.

2-4 μm, clear halo.

125

Sporotrichosis: Histology of spores.

4-6 μm, round or oval.

126

Pseudoepitheliomatous hyperplasia with suppurative and granulomatous inflammation: Differential diagnosis (3).

Deep mycoses.

Atypical mycobacterial infections.

Halogenodermas.

127

Cryptococcus: Alternative histology.

Xanthomatous infiltrate, especially in the immunocompromised.

128

Tuberculoid leprosy: Appearance of granulomas.

Elongated, surrounded by lymphocytes, arranged along neurovascular bundles.

129

Cutaneous leishmaniasis: Causes (3).

Old World: L. tropica.

New World: L. brasiliensis, L. mexicana.

130

Cutaneous leishmaniasis: Detection of parasites in a biopsy (2).

More likely to be seen in early lesions.

Giemsa stain can help.

131

Cutaneous leishmaniasis: Histology of late lesion.

Tuberculoid granulomas and lymphocytes.

Parasites may be undetectable.

132

Rhinoscleroma: Classic cell.

Mikulicz cell: Large histiocyte.

133

Granuloma inguinale:

A. Cause.
B. Inflammatory infiltrate.
C. Classic histologic finding.

A. Calymmatobacterium granulomatis.

B. Histiocytes and neutrophils.

C. Donovan body: Encapsulated, round to oval, 2-3 μm.

134

Leukocytoclastic vasculitis: Typically affected vessel in the skin.

Superficial dermal postcapillary venule.

135

Leukocytoclastic vasculitis: Bacterial cause.

Neisseria meningitidis.

136

Leukocytoclastic vasculitis: Immunofluorescence (2).

Most cases: IgM, C3, and fibrinogen around dermal vessels.

Henoch-Schönlein purpura: IgA.

137

Leukocytoclastic vasculitis: Chronic forms (2).

Erythema elevatum diutinum.

Granuloma faciale.

138

Livedo vasculitis: Anatomic location.

Lower legs.

139

Livedo vasculitis: Histology.

Fibrinoid matter in vessel walls leads to occlusion and ulceration.

Usually little inflammation.

140

Septic vasculitis: Histology.

Thrombi accompany leukocytoclastic vasculitis.

There may be intraepidermal pustules.

141

Causes of noninflammatory vasculitis of small vessels with deposits of pink matter in and around vascular lumens (4).

Monoclonal cryoglobulinemia.

TTP.

Warfarin- or heparin-induced vasculitis.

142

Superficial migratory thrombophlebitis: Associations (3).

Malignancy.

Hypercoagulable states.

Behçet's disease.

143

Superficial migratory thrombophlebitis: Typically affected vessel.

Small or medium-sized vein in deep dermis or subcutis of lower extremity.

144

Superficial migratory thrombophlebitis: Histology (3).

Occluding thrombus.

Neutrophils, lymphocytes, and histiocytes infiltrate muscle of vein.

Recanalization and resorption of thrombus occur with granulomatous reaction.

145

Superficial migratory thrombophlebitis: Histologic distinction from nodular vasculitis.

Nodular vasculitis affects arteries as well as veins.

146

Subcorneal pustular dermatosis: Clinical appearance.

Sterile pustules involving flexural surfaces and axillary and inguinal folds.

Groups of pustules may assume annular or serpiginous patterns.

147

Subcorneal pustular dermatosis: Histology (2).

Neutrophils beneath the stratum corneum and around superficial vessels.

Mild acantholysis may occur.

148

Subcorneal pustular dermatosis: Helpful ancillary tests.

Gram stain to exclude bullous impetigo.

Immunofluorescence to exclude autoimmune bullous diseases.

149

Subcorneal pustular dermatosis: Possible clinical association.

Monoclonal gammopathy, esp. IgA.

150

Pustular drug eruption / acute exanthematous pustular dermatosis: Histology (3).

Subcorneal or intraepidermal pustules.

Spongiosis.

Dermal eosinophils.

151

Pemphigus: Clinical appearance of bullae.

Large, flaccid, fragile; positive Nikolsky's sign.

152

Pemphigus: Anatomic distribution.

Scalp, around eyes, sternum, mid-back, umbilicus, groin.

Oral lesions can occur.

153

Pemphigus vulgaris: Histology of early lesion.

Eosinophilic spongiosis.

154

Pemphigus vulgaris:

A. Location of split.
B. Contents of bulla.
C. Inflammatory infiltrate.

A. Suprabasal.

B. Acantholytic keratinocytes.

C. Superficial dermal, often with eosinophils.

155

Pemphigus vegetans.

Variant of pemphigus vulgaris in which lesions heal with verrucous vegetations.

156

IgA pemphigus:

A. Histology.
B. Antigen.

A. Resembles subcorneal pustular dermatosis.

B. Desmocollin.

157

Pemphigus vulgaris: Direct immunofluorescence.

Intercellular IgG.

158

Location of staining by direct immunofluorescence in

A. Pemphigus vulgaris.
B. Pemphigus vegetans.
C. Pemphigus foliaceus.

A,B. Deep epidermis.

C. Superficial epidermis.

159

Location of staining by direct immunofluorescence in pemphigus erythematosus.

Superficial epidermis, or along the DEJ as in SLE.

160

Paraneoplastic pemphigus: Characteristic histological feature.

Interface dermatitis.

161

Paraneoplastic pemphigus: Direct immunofluorescence (2).

Intercellular IgG.

Granular IgG or IgM at DEJ may also be seen.

162

Paraneoplastic pemphigus:

A. Antigen.
B. Substrate for indirect immunofluorescence.

A. Desmoplakin.

B. Rat bladder.

163

Antigens involved in

A. Pemphigus vulgaris.
B. Pemphigus erythematosus.

A. Desmoglein III.

B. Desmoglein I, desmoglein III.

164

Hailey-Hailey disease:

A. Inheritance.
B. Histologic features not found in pemphigus vulgaris.

A. Autosomal dominant.

B. Full-thickness acantholysis, sparing of follicular epithelium.

165

Grover's disease: Histologic distinction from pemphigus vulgaris.

Grover's disease:

Acantholysis is more focal.

A single specimen may show a combination of keratinocytic abnormalities.

166

Darier's disease:

A. Inheritance.
B. Clinical appearance.

A. Autosomal dominant.

B. Hyperkeratotic papules in a follicular distribution.

167

Darier's disease: Histologic features not found in pemphigus vulgaris.

Corps ronds, grains.

Both diseases show suprabasal acantholysis.

168

Staphylococcal scalded-skin syndrome: Location of split.

In the granular layer.

169

Bullous pemphigoid: Clinical appearance of bullae.

Large, tense; negative Nikolsky's sign.

170

Bullous pemphigoid:

A. Location of split.
B. Contents of bulla.

A. Subepidermal.

B. Many eosinophils (except in the cell-poor variant).

171

Bullous pemphigoid: Histology of early lesion (2).

Eosinophilic spongiosis.

Superficial dermal eosinophils.

172

Bullous pemphigoid: Immunofluorescence (2).

DIF: C3 and IgG at the DEJ.

Salt-split skin: Antibodies on the ceiling of the bulla.

173

Bullous pemphigoid: Involved antigens.

BP1 and BP2 in the hemidesmosomes.

174

Pemphigoid gestationis: Distinction from bullous pemphigoid (2).

May show more neutrophils and necrosis of basal cells.

Clinical correlation often required.

175

Epidermolysis bullosa acquisita: Clinical presentation.

Acral blisters that heal with scarring.

176

Epidermolysis bullosa acquisita: Distinction from bullous pemphigoid.

Salt-split skin: Antibodies on the floor of the bulla.

177

Porphyria cutanea tarda: Histologic features (3).

Subepidermal bulla with minimal inflammation.

Festooning extension of dermal papillae into the cavity of the bulla.

PAS-positive perivascular deposits in the papillary dermis.

178

Cicatricial pemphigoid: Clinical presentation.

Bullae that involve mucous membranes and heal with scarring.

179

Dermatitis herpetiformis: Anatomic sites (5).

Elbows, knees, back, buttocks, scalp.

180

Dermatitis herpetiformis:

A. Location of split.
B. Contents of bullae.

A. Subepidermal.

B. Neutrophils, variable numbers of eosinophils.

181

Dermatitis herpetiformis: Histologic features in addition to bullae (2).

Neutrophils in tips of dermal papillae.

Superficial perivascular lymphocytes, neutrophils, eosinophils.

182

Dermatitis herpetiformis: Direct immunofluorescence.

Granular IgA in dermal papillae of normal skin and lesional skin.

183

Linear IgA dermatosis: Distinction from dermatitis herpetiformis.

Histology: May not be possible.

Direct immunofluorescence: Linear IgA at the DEJ.

184

Bullous systemic lupus erythematosus: Distinction from dermatitis herpetiformis.

Direct immunofluorescence: Granular IgG and C3 at the DEJ.

185

Eosinophilic pustular folliculitis:

A. Typical patients.
B. Histology.

A. Infants, immunocompromised.

B. Eosinophils in subcorneal pustules, in perifollicular infiltrates, and in spongiotic foci.

186

Majocchi's granuloma: Leading cause.

Trichophyton rubrum.

187

Follicular-occlusion triad.

Hidradenitis suppurativa.

Acne conglobata.

Perifolliculitis capitis abscedens et suffodiens.

188

Morphea / scleroderma: Early histology (2).

Perivascular and interstitial lymphocytes and plasma cells.

Thickening of bundles of collagen in the reticular dermis.

189

Morphea / scleroderma: Later histology (4).

Closely packed bundles of collagen.

Minimal inflammation.

Superficial displacement of eccrine glands.

Loss of other adnexa and of capillaries.

190

Morphea / scleroderma: Autoantibodies (2).

Morphea / CREST syndrome: Anticentromere.

Systemic sclerosis: Anti-Scl-70 (anti-topoisomerase).

191

Scleredema: Histology (2).

Collagen bundles are thickened but not hyalinized.

Hyaluronic acid fills widened spaces between collagen bundles.

192

Lichen sclerosus: Histology (4).

Epidermal atrophy.

Follicular plugging.

Basal vacuolar change.

Edema and homogenization of papillary dermis.

193

Radiation dermatitis: Vascular changes (2).

Superficial dermal telangiectasia.

Deep dermal blood vessels with fibrous thickening.

194

Nephrogenic systemic fibrosis:

A. Association.
B. Anatomic sites.

A. Renal disease.

B. Trunk and extremities.

195

Nephrogenic systemic fibrosis: Histology.

Thickened collagen bundles and CD34-positive spindled fibroblasts extending into subcutis and fascia.

196

Eosinophilic fasciitis: Histology.

Sclerosis and eosinophilic infiltrate of deep fascia.

197

Erythema nodosum: Anatomic location (2).

A. Acute: Extensor surfaces of legs; symmetrical.

B. Chronic: Legs; unilateral; recurrence at other sites.

198

Erythema nodosum: Associations (3).

Streptococcal pharyngitis.

Crohn's disease.

Sarcoidosis.

199

Erythema nodosum: Typical histology.

Granulomatous septal panniculitis that begins with lymphocytic and granulocytic inflammation.

200

Erythema nodosum: Ancillary test.

Special stains to exclude infectious (esp. tuberculous) panniculitis.

201

Subcutaneous fat necrosis of the newborn: Possible complications (2).

Hypercalcemia.

Thrombocytopenia.

202

Subcutaneous fat necrosis of the newborn: Histology.

Predominantly lobular inflammation.

Fat necrosis surrounded by macrophages and giant cells that contain a radial (or stellate) arrangement of needle-shaped lipid crystals.

203

Sclerema neonatorum: Distinction from subcutaneous fat necrosis of the newborn (2).

Sclerema neonatorum

Affects premature rather than full-term newborns.

Exhibits little or no inflammation.

204

Post-steroid panniculitis: Histology.

May resemble subcutaneous fat necrosis of the newborn; clinical history is essential.

205

Pancreatic fat necrosis: Distinguishing histologic features (2).

Ghostlike fat cells with thick borders.

No radially arranged lipid crystals.

206

Lipodystrophy: Histologic distinction from subcutaneous fat necrosis of the newborn.

Absence of needle-shaped crystals.

207

Erythema induratum: Histology.

Mixed lobular and septal panniculitis with vasculitis and zones of fat necrosis.

208

Epidermal-inclusion cyst:

A. Synonym.
B. Inherited cause of multiplicity.

A. Infundibular cyst.

B. Gardner's syndrome.

209

Steatocystoma multiplex: Inheritance.

Autosomal dominant.

210

Seborrheic keratosis: Name of keratin-filled cysts.

Horn cysts (pseudo−horn cysts if they communicate with the stratum corneum).

211

Squamous eddies vs. keratin pearls.

Squamous eddies: Whorls of keratinocytes without central parakeratosis; seen in irritated seborrheic keratoses.

Keratin pearls: Central parakeratosis; seen in SCC.

212

Dermatosis papulosa nigra: Histology.

Same as that of seborrheic keratosis.

213

Clear-cell acanthoma:

A. Age group.
B. Anatomic site.
C. Clinical appearance.

A. Middle-aged and older.

B. Lower extremities.

C. Ulceration; oozing surface.

214

Clear-cell acanthoma: Histology (3).

Abrupt change to pale keratinocytes.

Elongated rete ridges with well-vascularized dermal papillae.

Neutrophils among keratinocytes and in the overlying parakeratosis.

215

Clear-cell acanthoma: Cause of clearing of cells.

Glycogen.

216

Verruca plana: Anatomic sites (2).

Face.

Dorsa of hands.

217

Verruca plana: Histology (3).

Blunt epidermal papillae.

Parakeratosis but minimal hyperkeratosis.

Keratinocytes with viral changes.

218

Actinic keratosis vs. SCC in situ.

AK: Alternating parakeratosis and orthokeratosis; orthokeratosis at the follicular ostia.

SCC: Confluent parakeratosis.

219

Bowenoid papulosis vs. SCC in situ.

Indistinguishable by histology.

Bowenoid papulosis occurs as papules on genitals.

220

Keratoacanthoma: Inflammatory feature.

Microabscesses.

221

Verrucous carcinoma: Histology.

Tunnels of parakeratosis extending deep into the neoplasm.

Bulbous expansion of rete pegs ("elephant's feet").

222

Marjolin's ulcer.

SCC arising on the edge of a longstanding ulcer or scar.

223

Trichoepithelioma: Inheritance of multiplicity.

Autosomal dominant.

224

Trichoepithelioma vs. BCC: Immunohistochemistry.

Trichoepithelioma: CD10 in stromal cells only.

BCC: CD10 in epithelial and stromal cells.

225

Giant solitary trichoepithelioma.

Several centimeters in size; found in deep dermis and subcutis.

226

Pilomatricoma:

A. Age group.
B. Anatomic sites (3).

A. Children, adolescents.

B. Face, neck, upper extremities.

227

Pilomatricoma: Clinical association of multiplicity.

Myotonic dystrophy.

228

Pilomatricoma: Significance of shadow cells.

They are matrical cells that are failing to form hair shafts.

229

Trichilemmoma:

A. Silhouette.
B. Histology of desmoplastic type.

A. Verruciform.

B. Irregular extensions of clear cells into sclerotic dermis simulate invasive carcinoma.

230

Cowden's disease:

A. Inheritance.
B. Affected organs.

A. Autosomal dominant.

B. Malignancies may occur in breast, gastrointestinal tract, thyroid gland, reproductive organs.

231

Syndrome of multiple basal-cell carcinomas:

A. Name.
B. Other abnormalities (2).

A. Basal-cell-nevus syndrome.

B. Palmar keratotic pits, jaw cysts.

232

Syringoma: Clinical appearance.

Multiple yellow, firm papules, 1-3 mm.

233

Syringoma: Histology (3).

Cords and nests of monomorphous epithelial cells.

Comma-shaped ducts lined by two layers of cells and filled with proteinaceous matter.

Densely fibrotic stroma.

234

Syringoma: Special stain.

PAS

− May highlight contents of ducts.
− May stain cells of clear-cell syringoma (glycogen).

235

Syringoma vs. trichoepithelioma.

Trichoepithelioma contains keratin-filled infundibulocystic structures rather than ducts.

236

Syringoma vs. microcystic adnexal carcinoma.

MAC is solitary, larger, and extends deep into the dermis.

237

Poroma: Cell types.

Poroid cells: Dark.

Cuticular: Pale and forming tubules.

238

Poroma: Stroma.

Richly vascular.

239

Painful tumors of the skin.

Blue-rubber-bleb nevus.
Eccrine spiradenoma.
Neuroma, neurilemmoma.
Glomus tumor.
Angiolipoma.
Leiomyoma.

240

Spiradenoma:

A. Anatomic site.
B. Number.

A. Trunk and extremities.

B. Usually single but can be multiple.

241

Spiradenoma: Cell types (3).

Small, dark cells in the periphery of nodules.

Large, pale cells occupy the centers and line the tubules.

Lymphocytes.

242

Spiradenoma: Extracellular elements (2).

Hyaline basement-membrane-like matter.

Rich vascular supply.

243

Spiradenoma: Why painful?

Contains many unmyelinated axons.

244

Cylindroma: Type of differentiation.

Apocrine.

245

Cylindroma: Cell types.

Small, dark cells in the peripheral of nodules.

Large, pale cells occupy the centers and line the tubules.

246

Multiplicity of cylindromas:

A. Inheritance.
B. Gene and its location.

A. Autosomal dominant.

B. CYLD on 16q12.1.

247

Multiplicity of cylindromas may occur with multiplicity of what other tumor?

Trichoepithelioma.

248

Clear-cell hidradenoma:

A. Synonyms (3).
B. Basic architecture.

A. Nodular hidradenoma, solid-cystic hidradenoma, eccrine acrospiroma.

B. Nodule consisting of cellular lobules and cystic spaces.

249

Clear-cell hidradenoma: Cell types (2).

Clear cells make up the bulk of the tumor.

Cuboidal or columnar cells with decapitation secretion line the tubules.

250

Syringocystadenoma papilliferum:

A. Anatomic sites.
B. Associated proliferation.

A. Scalp, face.

B. Naevus sebaceus.

251

Syringocystadenoma papilliferum: Cells that line the papillae.

Luminal row: Columnar cells with occasional decapitation secretion.

Deeper row: Cuboidal cells.

252

Syringocystadenoma papilliferum: Stroma.

Full of plasma cells.

253

Syringocystadenoma papilliferum vs. hidradenoma papilliferum (2).

Hidradenoma papilliferum:

− No connection to the skin's surface.
− Papillae have one layer of cells (apocrine).

254

Syringocystadenoma papilliferum vs. tubular apocrine adenoma.

Tubular apocrine adenoma: No connection to skin's surface.

255

Microcystic adnexal carcinoma: Anatomic sites (4).

Upper lip (#1).

Chin, nasolabial fold, cheek.

256

Microcystic adnexal carcinoma: Histology.

Bland-appearing ductal structures, with or without keratin-filled cysts, infiltrate deep dermis, subcutis, and muscle, getting smaller toward the base.

Usually no connection to the surface.

257

Microcystic adnexal carcinoma: Clue to malignancy.

Perineural invasion.

258

Microcystic adnexal carcinoma: Behavior.

Locally aggressive but rarely metastasizes.

259

Naevus sebaceus: Age group.

Present at birth.

260

Naevus sebaceus:

A. Clinical development.
B. Histologic development.

A. Plaque-like in infancy, linear in childhood, verrucous and nodular at puberty.

B. Sebaceous glands are large at birth and in puberty, small in childhood.

261

Naevus sebaceus: Non-sebaceous histology (3).

Papillomatosis.

Follicular germs resembling BCC.

Apocrine glands deep in the dermis.

262

Naevus sebaceus: Tumors that can arise in it (3).

Benign: Trichoblastoma, syringocystadenoma papilliferum.

Malignant: BCC.

263

Naevus sebaceus vs. epidermal nevus.

Epidermal nevus lacks sebaceous lobules.

264

Sebaceous adenoma: Histology.

Increased basaloid cells at periphery of sebaceous lobules.

Mitotic figures may be present, but no nuclear atypia.

265

Sebaceous adenoma, rippled-pattern: Histology.

Parallel rows of monomorphous, fusiform cells that resemble Verocay bodies.

Sebaceous cells and ducts also present.

266

Sebaceous adenoma: Ancillary study.

IHC for loss of mismatch-repair proteins (MSH2/MLH1) should be considered.

267

Sebaceous carcinoma: Anatomic site.

Eyelid, particularly the meibomian glands and the gland of Zeis.

268

Sebaceous carcinoma: Histology (2).

Irregular lobules consisting of pleomorphic basaloid cells, sometimes with a few sebaceous cells in the center.

Eyelid: Pagetoid spread into conjunctiva or epidermis.

269

Sebaceous carcinoma: Relationship to SCC (2).

Sebaceous carcinoma can

− Arise in a site of SCC.
− Contain SCC-like squamoid areas.

270

Sebaceous carcinoma: Hormonal receptor.

Androgen receptor (demonstrable by IHC).

271

Sebaceous carcinoma: Predictors of poor prognosis (5).

Size greater than 1 cm.

Poor differentiation.

Multicentricity.

Extensive invasion of tissues.

Lymphovascular invasion.

272

Sebaceous carcinoma: Behavior in the Muir-Torre syndrome.

Much less likely to metastasize.

273

Giant congenital nevus: Benign associations (2).

Leptomeningeal melanocytosis.

Neurological disorders.

274

Giant congenital nevus: Malignant associations (2).

Melanoma, rhabdomyosarcoma.

275

Giant congenital nevus: Typical histologic feature.

Infiltration of nevus cells into septa of subcutaneous fat.

276

Congenital melanocytic nevus: Histology (2).

Nevus cells congregate around adnexa and blood vessels and infiltrate between collagen bundles.

277

Congenital melanocytic nevus: Histologic pitfall.

Presence of occasional mitotic figures in dermal nodules does not make it a melanoma.

278

Spitz nevus: Mitotic figures.

May be present but are usually not atypical and do not occur at the base of the lesion.

279

Spitz nevus: Non-melanocytic histology (3).

Epidermal hyperplasia with hyperkeratosis and orthokeratosis.

Papillary dermal vascular ectasia.

Patchy perivascular lymphocytes and histiocytes.

280

Halo nevus:

A. Age group.
B. Anatomic site.

A. Children and young adults.

B. Back.

281

Halo nevus: Histology of melanocytes.

Early: Large and atypical.

Late: Absent.

282

Special sites of melanocytic nevi (6).

Scalp.

Acral skin.

Periauricular skin.

Periumbilical skin.

Breasts.

Genitals.

283

Lentigo maligna: Clinical definition.

Melanoma in situ on sun-exposed skin.

284

Superficial spreading melanoma.

Melanoma with extensive pagetoid spread.

285

Clark's levels.

I: Melanoma in situ.

II: Extension into papillary dermis.

III: Filling of papillary dermis.

IV: Extension into reticular dermis.

V: Extension into subcutis.

286

Genes implicated in the pathogenesis of melanoma (6).

CMM1.

p16.

CDK4.

BRAF.

NRAS.

MEK (a kinase of MAP kinase).

287

Desmoplastic melanoma: Immunohistochemistry.

Positive: S100.

Negative: Mart-1, HMB45.

288

Angiokeratoma: Non-vascular histology.

Epidermal hyperplasia with hyperkeratosis.

289

Cavernous hemangioma: Syndromes (3).

Maffucci's: CH + multiple enchondromas.

Kasabach-Merritt: CH with thrombosis leading to consumptive coagulopathy.

Blue-rubber-bleb: CH + vascular proliferations in the gastrointestinal tract.

290

Pyogenic granuloma vs. bacillary angiomatosis.

Bacillary angiomatosis contains clumps of granular basophilic material in which bacilli can be identified with Warthin-Starry or Giemsa stain.

291

Kaposi's sarcoma: Epidemiological types (4).

Classic: Elderly men in S. and E. Europe.

Endemic: Young natives of Central Africa.

Epidemic: HIV patients.

Iatrogenic: Immunosuppressed patients.

292

Epidemic Kaposi's sarcoma: Anatomic sites.

Trunk, mucous membranes.

293

Kaposi's sarcoma, patch stage: Histology (3).

Slit-like spaces between collagen bundles.

Promontory sign.

Extravasated red blood cells.

294

Kaposi's sarcoma, plaque stage: Histology (3).

Short fascicles of spindle cells.

Diffuse proliferation of irregular vascular spaces.

Intracytoplasmic hyaline globules.

295

Kaposi's sarcoma, nodular stage: Histology (4).

Spindle cells and vascular spaces form nodules.

Nuclear atypia and mitotic figures.

Extravasated red cells and hemosiderin-laden macrophages.

Conspicuous hyaline globules.

296

Kaposi's sarcoma, late aggressive stage: Histology.

Resembles aggressive sarcoma.

297

Kaposi's sarcoma: Special staining of hyaline globules.

PAS positive, diastase resistant.

298

Epithelioid angiosarcoma: Morphology of neoplastic cells.

Large and pleomorphic; abundant eosinophilic cytoplasm; large nucleus with large nucleolus.

299

Epithelioid angiosarcoma: Histologic architecture (2).

Asymmetrical proliferation.

May lack distinct vascular spaces and thus resemble carcinoma or melanoma.

300

Epithelioid angiosarcoma vs. epithelioid hemangioma.

Epithelioid hemangioma:

− Symmetrical.
− No nuclear atypia.

301

Angiosarcoma: Immunohistochemistry (4).

CD31, CD34, ERG.

Lymphatic tumors: D2-40.

302

Angiosarcoma: Electron microscopy.

Weibel-Palade bodies (rod-shaped; resemble lysosomes).

303

Dabska tumor.

Malignant intravascular papillary angioendothelioma.

304

Angioleiomyoma: Anatomic site.

Extremities, esp. lower extremities.

305

Dartoic leiomyoma:

A. Anatomic sites.
B. Clinical presentation.

A. Scrotum, labium majus, areola.

B. Painless (unlike other leiomyomas).

306

Cutaneous leiomyosarcoma:

A. Age group.
B. Anatomic sites.

A. Second and third decades.

B. No anatomic predilection.

307

Cutaneous leiomyosarcoma:

A. Histologic architecture.
B. Metastasis.

A. Asymmetrical; forms fascicles; intermixed zones of hypercellularity and of better differentiation.

B. Hematogenous.

308

Keloid: Change in histology with age.

Early lesions: More vascular.

Older lesions: More fibrous.

309

Keloid vs. hypertrophic scar.

Hypertrophic scar:

− Limited to area of injury.
− Less myxoid matrix.

310

Dermatofibrosoma: Clinical sign.

Fitzpatrick's sign: Pinching the lesion results in a dimple.

311

Dermatofibroma: Aneurysmal variant.

Vascular proliferation and hemosiderin.

312

Dermatofibroma: Cellular type.

Densely cellular; increased mitotic figures.

313

Dermatofibroma: Immunohistochemistry.

Positive: Factor XIIIa.

Negative: CD34 (except at periphery of cellular DF).

314

Dermatofibrosarcoma protuberans: Change in clinical appearance with age.

Early: Tan or brown nodule, slow-growing.

Later: Blue-red, multilobular nodule, rapidly growing.

315

Dermatofibrosarcoma protuberans:

A. Overlying epidermis.
B. Invasion of fat.
C. Cytological atypia and mitosis.

A. Atrophic.

B. Replacement or lacelike infiltration.

C. Present but not prominent.

316

Dermatofibrosarcoma protuberans: Translocation.

t(17;22) :: COL1A1−PDGFB.

317

Dermatofibrosarcoma protuberans: Variant.

Bednar tumor contains pigmented spindle cells.

318

Neurofibroma: Preferred anatomic sites (2).

Palms, soles.

319

Neurofibroma: Cellular components.

Schwann cells.

Fibroblasts.

(Mast cells in the background.)

320

Schwannoma: Zones of Antoni.

Antoni A: Hypercellular.

Antoni B: Hypocellular; mucinous background.

321

Dermatofibroma vs. neurofibroma: Overlying epidermis.

DF: Hyperplastic, with pigmented basal cells.

NF: Atrophic, with indistinct rete ridges.

322

Merkel-cell carcinoma: Anatomic sites.

Head.

Extremities.

323

Merkel-cell carcinoma: Associated epithelial malignancy.

Squamous-cell carcinoma.

324

Merkel-cell carcinoma: Cytokeratin stain.

Positive for CK20.

325

Merkel-cell carcinoma: Electron microscopy.

Membrane-bound dense granules; perinuclear bundles or whorls of intermediate filaments.

326

Merkel-cell carcinoma: Divergent differentiation (3).

Squamous.

Adnexal.

Melanocytic.

327

Urticaria pigmentosa: Four forms.

Arising in infancy or childhood without systemic lesions.

Arising in adolescence or adulthood without systemic lesions.

Systemic mast-cell disease.

Mast-cell leukemia.

328

Urticaria pigmentosa: Age group in which ___ lesions appear.

A. solitary
B. diffuse erythrodermic
C. telangiectasia macularis eruptiva perstans

A, B. Infants.
C. Adults.

329

Urticaria pigmentosa: Age group in which ___ lesions appear.

A. maculopapular
B. nodular and plaquelike

Both: Infants and adults.

330

Urticaria pigmentosa: Arrangement of mast cells in ___ lesions.

A. nodular and plaquelike
B. maculopapular and TMEP
C. erythrodermic

A. Throughout the dermis.

B. Around upper dermal blood vessels.

C. In a dense band in the upper dermis.

331

Urticaria pigmentosa: Location of split in the bullous type.

Subepidermal.

332

Urticaria pigmentosa: Stains for mast cells (5).

Giemsa, toluidine blue, Leder's.

CD117, tryptase.

333

Systemic mast-cell disease: Affected organs (6).

Bones.

Lymph nodes, spleen.

Liver.

Gastrointestinal tract.

Central nervous system.

334

Letterer-Siwe disease:

A. Age group.
B. Clinical presentation.
C. Locations of skin lesions.

A. 3 months to 3 years.

B. Constitutional symptoms, extraosseous lesions.

C. Scalp, face, mouth, neck, trunk.

335

Hand-Schüller-Christian disease:

A. Age group.
B. Clinical presentation.
C. Classic triad.

A. 2-6 years.

B. Otitis media plus all or part of the classic triad.

C. Defects in cranial bones, exophthalmos, diabetes insipidus.

336

Hand-Schüller-Christian disease: Locations of skin lesions (3).

Chest, axillae, groin.

337

Eosinophilic granuloma:

A. Age group.
B. Locations of internal lesions.
C. Locations of skin lesions.

A. 2-5 years.

B. Bones, lungs.

C. Scalp, face, mouth, groin.

338

Langerhans'-cell histiocytosis: Arrangement of Langerhans' cells.

Throughout the dermis and often in the epidermis.

339

Langerhans'-cell histiocytosis:

A. Immunohistochemistry.
B. Electron microscopy.

A. Positive: S100, CD1a, langerin.

B. Birbeck granules within Langerhans' cells.

340

Langerhans'-cell histiocytosis: Possible genetic defect.

Activating mutation of BRAF.

341

Congenital self-healing reticulohistiocytosis: Clinical course.

Appears at birth or shortly thereafter.

Involution begins at 2-3 months.

Gone within 1 year.

342

Mycosis fungoides, patch stage: Histology.

Lymphocytes form a patchy infiltrate in a papillary dermis with thickened collagen bundles.

Lymphocytes form small collections within a minimally spongiotic epidermis.

There may be psoriasiform hyperplasia.

343

Mycosis fungoides, plaque stage: Histology.

Similar to that of patch stage, but with denser and more bandlike infiltrate.

344

Mycosis fungoides, tumor stage: Histology.

Atypical lymphocytes form diffuse infiltrate.

There are more medium and large lymphoid cells.

345

Mycosis fungoides: Large-cell transformation.

More than 25% of tumor cells are large cells, or there are discrete nodules of large cells.

346

Mycosis fungoides: Immunophenotype (4).

Positive: CD3, CD4, CD5.

Negative: CD8 (except in younger patients).

CD7 is diminished or lost.

CD30 is positive in large-cell transformation.

347

Mycosis fungoides: Sézary's syndrome.

Erythrodermic mycosis fungoides + circulating tumor cells.

348

Mycosis fungoides: Related skin lesion.

Follicular mucinosis.

349

Cutaneous anaplastic large-cell lymphoma: Epidermal change.

Ulceration.

350

Cutaneous anaplastic large-cell lymphoma vs. lymphomatoid papulosis.

LP: Mixed infiltrate; fewer atypical lymphocytes.

351

CD30-positive lymphomas of the skin (3).

Anaplastic large-cell lymphoma.

Mycosis fungoides, late stage.

Pleomorphic T-cell lymphoma.