Case report of squamous cell cancer arising in perineal epidermal inclusion cyst, presenting as rapidly enlarging and cavitating lesion.

Introduction: Cutaneous squamous cell cancer (cSCC) is a common condition, with straight forward and well-known heuristics regarding diagnosis, treatment, and surveillance. cSCC arising in an epidermal inclusion cyst is rare, but not unheard of. In contrast, the authors' are unaware of any prior reports of cSCC arising in an epidermal inclusion cyst within an atypical cavernous and cavitating lesion in the perineum.