Dermatopathology and Histology Flashcards

Verocay bodies are a histological feature associated with which cutaneous tumor?

Answer: Schwannoma (neurilemmoma)

Verocay bodies are palisading arrangements of Schwann cell nuclei around acellular fibrillar material (Antoni A areas), pathognomonic of schwannoma.

Solar elastosis is characterized by which histological finding in the dermis?

Answer: Basophilic degeneration and clumping of elastic fibers

Solar elastosis results from chronic UV exposure causing abnormal production and degeneration of elastic fibers, which appear basophilic/amphophilic and clumped on H&E staining.

Which direct immunofluorescence pattern is characteristic of pemphigus vulgaris?

Answer: Intercellular IgG in a 'chicken wire' pattern

Pemphigus vulgaris shows intercellular IgG deposits creating a 'chicken wire' or 'fish net' pattern throughout the epidermis due to anti-desmoglein autoantibodies.

Which histochemical stain is most useful for identifying amyloid deposits in the skin, and what is its characteristic finding under polarized light?

Answer: Congo red stain showing apple-green birefringence

Congo red staining with apple-green birefringence under polarized light is the gold standard for identifying amyloid deposits in skin and other tissues.

Palisading granulomas with central necrobiosis of collagen and mucin are the histological hallmark of which condition?

Answer: Granuloma annulare

Granuloma annulare is characterized by palisading histiocytes surrounding central zones of degenerated collagen and mucin deposition in the dermis.

'Naked granulomas' (non-caseating granulomas with sparse surrounding lymphocytes) in skin biopsies are characteristic of which systemic condition?

Answer: Sarcoidosis

Sarcoidosis produces 'naked' non-caseating epithelioid granulomas with minimal surrounding lymphocytic infiltrate, often with Langhans giant cells and inclusion bodies.

Which histological feature best characterizes Kaposi sarcoma and distinguishes it from other vascular tumors?

Answer: Slit-like vascular spaces with spindle cells and extravasated erythrocytes

Kaposi sarcoma shows slit-like irregular vascular spaces lined by spindle cells with extravasated red blood cells and hemosiderin deposition, reflecting its HHV-8-driven spindle cell proliferation.