A Treatment-Refractory, Perianal Tumor Arising in an Otherwise Healthy Older Adult Woman

A woman in her 80s presented with a growing, painful tumor on her buttock with epithelial hyperplasia, ulceration, focal multinucleated keratinocytes, and herpes simplex virus positivity. What is your diagnosis?
Source: JAMA Dermatology - Category: Dermatology Source Type: research