Pathology Flashcards
Dermatofibroma
Common, benign lesions usually on the extremities
Hist: Non-encapsulated masses of interlacing fascicles of spindle-shaped cells. Epidermal hyperplasia with hyperpigmented rate ridges
Basal Cell Carcinoma
Pearly papule on head and neck that may be telangectasic or ulcerated (rat bite)
Carcinoma insitu, rarely metastasizes
HIST: Palisades of basal cells with dark nuclei
Squamous Cell Carcinoma
Second most common tumor on sun exposed skin, more common in men
Nodule with central ulceration and a pink elevated indurated border
HIST: Invasive carcinoma arising from epidermis. Pleomorphism, nuclear hyperchromasia, intercellular bridges, and atypical mitotic figures. Keratin pearls
Can arise from actinic keratosis
Melanoma
de novo melanocytic lesions with ABCDE characteristics.
HIST: Large, irregular, hyperchromatic nuclei, ofter with prominent nucleoli. Pagetoid spread of malignant cells into epidermis.
Radial and vertical growth
BRAF and NRAS
HMB-45 immunohistochemical stain
Dermal inflammatory infiltrate present
Most common tumor of eye
Epidermal Inclusion Cyst
Common lesions formed by invagination of the epidermis and filled with keratin and lipid debris. Well circumscribed, firm, movable and located in the dermis of subcutaneous tissue.
Cystic cavities have soft white substance (keratin) inside. If ruptured may have inflammatory response.
HIST: wall resembling normal epidermis. Center is keratin that looks like shredded wheat
Tinea Corporis
Elevated annular plaque. Raised erythematous, papulovesicular border. Some crusting and scaling. Center less involved.
HIST: hyperkeratosis with neutrophils, parakeratosis, acanthosis, and perivasicular upper dermal lymphocytic infiltrate.
Verruca Vulgaris
GROSS: small, well circumscribed, skin colored or pink papules. Redish brown to black dots on surface due to thrombosed capillaries are characteristic.
HIST: Hyperkeratosis, acanthosis, papallomatosis, rete ridge elongation with inward curvature at edge of lesion.
Contact Dermatitis
Acute diffuse erythema, edema, oozing and crusting of the skin with associated vessicles and bullae. Linear lesions may be noted. Chronic form has scaling or thickened skin
HIST: spongiosis and intra epidermal vesicles. Chronic form has hyperkeratosis and acanthosis. PMN infiltrate with all stages. Type 4 hypersensitivity reaction
Pemphigus vulgaris
GROSS: easily ruptured vesicles and bullae. Chest, face, scalp, oral mucosa, axilla, groin and umbilicus. Large areas of painful erosions in full-blown disease.
HIST: Intraepidermal bullae that split epidermis above basal cell layer. Direct immunoflorescence show IgG and C3. Noticeable weight loss. Type II auto immune. Anti-desmoglien-3.
Bullus pemphigoid
Large bulla that do not rupture easily.
HIST: IgG and C3 found in basement membrane. Acantholysis of keratinocytes. Anti-Dystonin or Type XVII collegen antibodies
Erythema multiforme
Adult onset inflammatory disease with oral and skin lesions on extensor aspects of extremities. May have fever and weakness. Lesions may itch or burn.
GROSS: Target appearance of papule with central vesicle. Concentric zones of color chage. Bilateral and symmetric.
HIST:Perivascular mononuclear infiltrate.
Stevens Johnson Syndrome-severe mucosal involvement
Toxic Epidermal Necrosis- drug allergy
NSAIDS, Motrin, Sulfa, barbiturates, pennicillin
Psoriasis
Inflammatory dermatosis wide range of severity
GROSS: Sharply demarkated erythematous papules and plaques covered by scales on scalp, sacral region, extensor surfaces of extremities umbilicus, penis, and nails. May be pustular or guttate.
HIST: Parakeratosis, Acanthosis, Elongation of Rete Ridges, Elongation of the papillary dermis, PMN and Munro microabcesses in parakeratotic layer.
Seborrectic keratosis
Common in old people on the trunk, face, and extremities. Papules enlarge and have a stuck on appearance. Vary in color.
HIST:Hyperkeratosis, acanthosis, papillomatosis, melanocytic hyperplasia, horn cysts. Straight line across bottom of epidermis.
Zellweger Syndrome
Defect in peroxisomal biogenesis causes accumulation of VLCFA in tissues (mainly liver and brain)
Symptoms: retinitis pigmentosa, cerebellar ataxia, chronic polyneuropathy
Sign: Increased C26:0 and C26:1 fatty acids in plasma
Alpha-hydroxylase Deficiency
Rare autosomal recessive disorder results in accumulation of Phytanic Acid (from plants) in tissues
Symptoms: mainly neurologic
Treatment: dietary restriction
