Publication:

Squamous Cell CarcinomaDeveloped in a TrichilemmalCyst, an Incidental Finding

A 61-year-old man with no previous cancer history attended the dermatology clinic with a three-year history of asymptomatic swelling on the posterior aspect of the left elbow. Physical examination revealed a subcutaneous nodule of 1cm in diameter, with no epidermal changes. A Doppler ultrasound was requested, which revealed a predominantly dermal hypodermal cystic lesion with hypoechogenic content, an echogenic rim and small echogenic foci compatible with an epidermal cyst, no solid inner nodule was depicted (Fig. 1). An excisional biopsy was performed, which revealed a trichilemmal-type follicular cyst with a 0.5mm thickness well-differentiated squamous cell carcinoma (SCC) in its wall (Fig. 2). It was presented to the oncology committee that suggested local extent of 1cm The new biopsy did not show signs of residual neoplasia. At six months of follow-up, the patient did not present clinical or dermoscopic signs of recurrence.