Proliferating trichilemmal cyst occurring on the shin

Area of Science:

• Dermatology
• Pathology

Background:

• Proliferating trichilemmal cysts (PTCs) are uncommon benign adnexal neoplasms.
• These cysts typically manifest on sun-exposed areas, predominantly the scalp and occasionally the upper trunk.

Observation:

• A case report of a patient presenting with a proliferating trichilemmal cyst on the shin is described.
• Clinical and histological examinations were performed to characterize the lesion.

Findings:

• Histological examination confirmed the typical features of a proliferating trichilemmal cyst.
• This represents the first documented instance of a PTC occurring on the leg.

Implications:

• This case expands the known anatomical distribution of proliferating trichilemmal cysts.
• Highlights the importance of considering PTCs in the differential diagnosis of leg lesions, even in atypical locations.