INFECTIONS AND INFESTATIONS

Question 1

Patterns for syphilis

Answer 1

Psoriasiform +lichenoid

Question 2

What are the features of syphilis

Answer 2

• Predominant infiltrate: plasma cell (has eccentric, clock-face nucleus)
• Endothelial swelling
• Warthin-Starry: stains spirochetes

Question 3

stain for spirochetes

Answer 3

Warthin-Starry: stains spirochetes

Question 4

features of TB VERRUCOSA CUTIS

Answer 4

Scanty focal granuloma, psoriasiform + lichenoid AFB typically negative

Question 5

features of LUPUS VULGARIS

Answer 5

More organized granuloma, caseation necrosis, variable epidermal changes AFB +/-

Question 6

features of scrofuloderma

Answer 6

Mixed inflammation, granuloma, marked fibrosis, caseation necrosis AFB +/-

Question 7

hallmark of cutaneous TB

Answer 7

TUBERCULOID GRANULOMA

Question 8

Identify the type of granuloma

Answer 8

Tuberculoid granuloma
- epithelioid histiocytes with surrounding mantle of lymphocytes

Question 9

identify the pointed structure

Answer 9

Langhans giant cells - granuloma with multinucleated giant cells

Question 10

Answer 10

Tuberculoid Caseating Granuloma

• Caseation: focal eosinophilic area od necrotic collagen surrounded by rim of histiocytes

Question 11

Answer 11

Caseation necrosis

Question 12

Pattern of cutaneous tuberculosis

Answer 12

GRANULOMATOUS

TVC: psoriasiform + Lichenoid

Scrofuloderma: diffuse

Question 13

pattern of erythema induratum

Answer 13

Predominantly lobular panniculitis with vasculitis

Features:
- Histiocytes + mutinucleated giant cells
- Mixed cell infiltrate
- Small to medium-sized vasculitis

Question 14

pattern of tuberculoid leprosy

Answer 14

Granulomatous - nodular (superficial and deep)

Question 15

pattern of lepromatous leprosy

Answer 15

Granulomatous - diffuse (superficial and deep)

Question 16

Identify spectrum of leprosy

Answer 16

TUBERCULOID LEPROSY

• (-) grenz zone
• Well-organized granulomas (may be elongated/linear)

Question 17

Identify spectrum of leprosy

Answer 17

LEPROMATOUS LEPROSY

• (+) grenz zone
• diffuse foamy histiocytes

Question 18

Answer 18

Tuberculoid: nodular (tight, ‘stretched-out’ granulomas)

Tuberculoid: epithelioid +/- giant cells

Question 19

Answer 19

Lepromatous: foamy + globi

Question 20

Identify spectrum of leprosy

Answer 20

BORDERLINE TUBERCULOID

• Focal/incomplete grenz zone
• Epithelioid histiocytes +/- giant cells

Question 21

Identify spectrum of leprosy

Answer 21

BORDERLINE BORDERLINE

• Poorly organized epithelioid granulomas
• Epithelioid + Foamy histiocytes

Question 22

Identify spectrum of leprosy

Answer 22

BORDERLINE LEPROMATOUS

• Poorly to moderately defined, loose granulomas
• Epithelioid < Foamy histiocytes

Question 23

Pattern of Erythema Nodosum Leprosum

Answer 23

Predominantly lobular panniculitis with vasculitis Superficial and deep, nodular and diffuse infiltrates

Feature: Diffuse infiltrates of neutrophils

Question 24

Answer 24

HERPES SIMPLEX/VARICELLA

Intraepidermal blister

• ballooning of keratinocytes (INTRACELLULAR EDEMA)
• acantholysis

✓ Pale necrotic keratinocytes
✓ Steel gray nuclei
✓ Molding and margination of nuclear chromatin
✓ Multinucleation of keratinocytes
✓ Ground glass inclusions
✓ +/- leukocytoclastic vasculitis

Question 25

Answer 25

MOLLUSCUM CONTAGIOSUM

Endophytic bulbous acanthosis / Crateriform invagination
Henderson-Patterson bodies (intracytoplasmic inclusion bodies)

Question 26

Answer 26

VERRUCA VULGARIS

Papillomatous architecture
Inward bending of rete ridges

Features:

• Koilocytes: vacuolated cells with basophilic nuclei surrounded by a clear halo
• Hyperkeratosis with tiers of parakeratosis
• Hypergranulosis with enlarged keratohyaline granules
• Dilated vessels in the dermis

Question 27

Answer 27

Dermatophytosis

Question 28

Answer 28

DERMATOPHYTOSIS

Superficial perivascular; Spongiosis

• Sandwich sign: PAS positive hyphae in the parakeratotic stratum corneum
• Subcorneal pustule as a clue

Question 29

Answer 29

TINEA VERSICOLOR

Pattern/s: Superficial perivascular dermatitis / invisible dermatosis

• Intracorneal hyphae (spaghetti) and spores (meatballs)

Question 30

Answer 30

MAJOCCHI’S GRANULOMA

Granulomatous; Periinfundibulitis, perifolliculitis + neutrophilic microabscess

• Spores and hyphae within the dermis and follicular infundibulum
• Mixed cell infiltrate
  +/- ruptured follicle

Question 31

Answer 31

CHROMOMYCOSIS

Pattern/s: Granulomatous + Pseudoepitheliomatous hyperplasia +Suppurative

• Round, brown, thick-walled yeast forms: Medlar bodies/ sclerotic bodies (“copper pennies”)
• Neutrophilic abscesses within epidermis

Question 32

Answer 32

EUMYCETOMA

• Granulomatous, nodular to diffuse
• Granules
• Diffuse mixed cell infiltrate
• Focal neutrophilic abscesses
• (+/-) giant cells
• Splendore-hoeppli phenomenon: eosinophilic rim surrounding granule

Question 33

Answer 33

CRYPTOCOCCOSIS

Pattern/s: Granulomatous, diffuse; “soap bubble appearance”; Suppurative

• Mucoid dermal infiltrate
• Giant cells
• Spherical yeast with mucoid capsule
• STAINS:
  
  • PAS highlights cell wall with red
  • Yeast cells stain black with GMS
  • Capsule stains with alcian blue and mucicarmine

Question 34

Answer 34

AMASTIGOTES OF LEISHMANIASIS

Pattern: Granulomatous

• Histiocytes with amastigotes (Leishman-Donovan bodies)
• Dense dermal infiltrate of lymphocytes, histiocytes, plasma cells
• Giemsa stain: highlights organism

Question 35

Answer 35

SCABIES

-Spongiosis; Epidermal hyperplasia
- Eosinophils
- Dense diffuse and nodular mixed infiltrate
- Eggs, mites or sycbala (eggs) in the stratum corneum