Resident Dermatologist: Kevin Donnelly, MD

Attending Dermatologist: Susan Massick, MD

Dermatopathologist: Catherine Chung, MD


A 32 year old male patient presents for a lesion on his right inner thigh. Patient reports the lesion has been present since he was 6 years old. It has been slowly growing larger. It had previously been asymptomatic, but recently it has been growing faster and become sore to touch. He reports no prior treatment or evaluation of the lesion. He is otherwise healthy with no medical problems. Patient was sent for excisional biopsy.

5.5 cm x 2.7 cm firm hyperpigmented nodule on right inner upper thigh.

closer view of lesion.

At low power, the entire dermis is replaced by a diffuse and densely cellular infiltrate that infiltrates into the subcutis.

High power view reveals the cells to be spindled in shape and arranged in a “storiform” or “cartwheel” arrangement.

The lesional cells express CD34.

Deep infiltration of the fat in which the subcutis is replaced by tumor cells is characteristic.

What is the most likely diagnosis?

  1. Sarcoidosis
  2. Keloid
  3. Neurofibroma
  4. Plexiform Neurofibroma
  5. Dermatofibroma
  6. Dermatofibrosarcoma protuberans
Dermatofibrosarcoma protuberans