ABD Dermatopathology 2

Question 1

A skin biopsy shows a 'sawtooth' pattern of the rete ridges with a band-like lymphocytic infiltrate at the dermoepidermal junction. What is the diagnosis?

Accepted Answer

Lichen planus

Answer

Sawtooth rete ridges with a band-like (lichenoid) interface lymphocytic infiltrate are classic for lichen planus.

Question 2

Munro microabscesses (collections of neutrophils in the stratum corneum) are a characteristic histologic feature of which condition?

Accepted Answer

Psoriasis

Answer

Munro microabscesses in the parakeratotic cornified layer are a hallmark of psoriasis.

Question 3

A pigmented lesion demonstrates nests of melanocytes at both the dermoepidermal junction and within the dermis. This architecture defines which nevus type?

Accepted Answer

Compound nevus

Answer

A compound nevus has melanocytic nests in both the epidermis (junctional component) and the dermis.

Question 4

Which stain is most useful for highlighting mucin deposition in the dermis, as seen in lupus erythematosus?

Accepted Answer

Colloidal iron (or Alcian blue)

Answer

Colloidal iron and Alcian blue stain acid mucopolysaccharides, highlighting dermal mucin.

Question 5

A dermal tumor shows a proliferation of spindle cells with a 'storiform' (cartwheel) pattern and entraps fat, extending into subcutis. Which is most likely?

Accepted Answer

Dermatofibrosarcoma protuberans

Answer

A storiform spindle-cell proliferation infiltrating fat in a honeycomb pattern and CD34-positive is characteristic of DFSP.

American Board of Dermatology (ABD) Practice Test

American Board of Dermatology (ABD) Practice Test

ABD Dermatopathology 2