Race for the Case answers

Diagnose this new case by Madeleine Medvedev, MD, and Alejando Barrera-Godínez, MD, IFAAD

A 22-year-old male patient with no significant past medical history presents to clinic with a “spot on the scalp.” It was present since birth, though over the past few years has been growing and bleeding. Initially, it was not bothersome though more recently can be tender on palpation. The patient denies a personal or family history of skin cancer.

1. Biopsy showed a typical “fjords and fronds” appearance. What other cell type would be present (usually within the cores of the fronds)?

Answer: Plasma cells

2. Based on the diagnosis, within what primary lesion did this occur?

Answer: The diagnosis is a syringocystadenoma papilliferum and occurred within a nevus sebaceous.

3. What is the most common secondary neoplasm that can occur within this patient’s primary lesion?

Answer: Trichoblastoma

4. What is the main histologic differential diagnosis of this lesion? On histology, it would show a maze-like configuration and usually occurs on the vulva/perineum.

Answer: Hidradenoma papilliferum

5. If this lesion was not removed via biopsy for this patient, is there a high likelihood of malignant transformation?

Answer: No