Resident Dermatologist: Stephanie Saed, MD

Attending Dermatologist: Susan Massick, MD

Dermatopathologist: Catherine Chung, MD

HISTORY:

A 40 year old healthy Caucasian female presents with a slowly growing lesion on her forehead. The lesion has been present for over a decade. The lesion is sometimes itchy and only mildly painful. (Figure 1)

Shave biopsy demonstrates well-circumscribed aggregates of basphilic cells that occupy the dermis.

The aggregates are surrounded by a prominent pink basement membrane (yellow arrow) and contain pink hyaline droplets (blue arrow).

What is the most likely diagnosis?

  1. Pilar cyst
  2. Basal cell carcinoma
  3. Cylindroma
  4. Epidermal inclusion cyst
Cylindroma