Flashcards in Skin Deck (352)
Seborrheic keratosis: Name of keratin-filled cysts.
Horn cysts (pseudo−horn cysts if they communicate with the stratum corneum).
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.
Dermatosis papulosa nigra: Histology.
Same as that of seborrheic keratosis.
A. Age group.
B. Anatomic site.
C. Clinical appearance.
A. Middle-aged and older.
B. Lower extremities.
C. Ulceration; oozing surface.
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.
Clear-cell acanthoma: Cause of clearing of cells.
Verruca plana: Anatomic sites (2).
Dorsa of hands.
Verruca plana: Histology (3).
Blunt epidermal papillae.
Parakeratosis but minimal hyperkeratosis.
Keratinocytes with viral changes.
Actinic keratosis vs. SCC in situ.
AK: Alternating parakeratosis and orthokeratosis; orthokeratosis at the follicular ostia.
SCC: Confluent parakeratosis.
Bowenoid papulosis vs. SCC in situ.
Indistinguishable by histology.
Bowenoid papulosis occurs as papules on genitals.
Keratoacanthoma: Inflammatory feature.
Verrucous carcinoma: Histology.
Tunnels of parakeratosis extending deep into the neoplasm.
Bulbous expansion of rete pegs ("elephant's feet").
SCC arising on the edge of a longstanding ulcer or scar.
Trichoepithelioma: Inheritance of multiplicity.
Trichoepithelioma vs. BCC: Immunohistochemistry.
Trichoepithelioma: CD10 in stromal cells only.
BCC: CD10 in epithelial and stromal cells.
Giant solitary trichoepithelioma.
Several centimeters in size; found in deep dermis and subcutis.
A. Age group.
B. Anatomic sites (3).
A. Children, adolescents.
B. Face, neck, upper extremities.
Pilomatricoma: Clinical association of multiplicity.
Pilomatricoma: Significance of shadow cells.
They are matrical cells that are failing to form hair shafts.
B. Histology of desmoplastic type.
B. Irregular extensions of clear cells into sclerotic dermis simulate invasive carcinoma.
B. Affected organs.
A. Autosomal dominant.
B. Malignancies may occur in breast, gastrointestinal tract, thyroid gland, reproductive organs.
Syndrome of multiple basal-cell carcinomas:
B. Other abnormalities (2).
A. Basal-cell-nevus syndrome.
B. Palmar keratotic pits, jaw cysts.
Syringoma: Clinical appearance.
Multiple yellow, firm papules, 1-3 mm.
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.
Syringoma: Special stain.
− May highlight contents of ducts.
− May stain cells of clear-cell syringoma (glycogen).
Syringoma vs. trichoepithelioma.
Trichoepithelioma contains keratin-filled infundibulocystic structures rather than ducts.
Syringoma vs. microcystic adnexal carcinoma.
MAC is solitary, larger, and extends deep into the dermis.
Poroma: Cell types.
Poroid cells: Dark.
Cuticular: Pale and forming tubules.