Dermatopathology and Histology Flashcards

Which histological finding is considered pathognomonic of psoriasis?

Answer: Munro microabscesses

Munro microabscesses are collections of neutrophils within the parakeratotic stratum corneum and are pathognomonic of psoriasis.

In which epidermal layer are melanocytes primarily located?

Answer: Stratum basale

Melanocytes reside in the stratum basale (basal layer), where they synthesize melanin and transfer it to surrounding keratinocytes via dendrites.

In dermatopathology, 'spongiosis' refers to which histological finding?

Answer: Intercellular edema within the epidermis

Spongiosis is intercellular edema between keratinocytes, causing the epidermis to appear sponge-like on histology and is the hallmark of eczematous dermatitis.

Civatte bodies (colloid/hyaline bodies) are characteristic of which dermatological condition?

Answer: Lichen planus

Civatte bodies are apoptotic keratinocytes (eosinophilic globules) seen at the dermal-epidermal junction in lichen planus due to interface dermatitis.

Subepidermal blisters with neutrophilic microabscesses in dermal papillae are histologically characteristic of which condition?

Answer: Dermatitis herpetiformis

Dermatitis herpetiformis shows subepidermal blisters with neutrophil-rich microabscesses at dermal papillae tips, corresponding to granular IgA deposits.

Parakeratosis is defined as which histological finding?

Answer: Retention of nuclei within the stratum corneum

Parakeratosis is the retention of nuclei in the stratum corneum, indicating abnormal keratinization and rapid epidermal turnover, as seen in psoriasis.

Which histological feature best distinguishes superficial spreading melanoma from a benign compound nevus?

Answer: Pagetoid spread of melanocytes into upper epidermal layers

Pagetoid spread refers to single melanocytes or nests ascending into the upper epidermis, a hallmark of melanoma not seen in benign nevi.