Proliferating trichilemmal tumour of the eyelid in a 7-year-old girl.

Proliferating trichilemmal tumours (PTTs) are rare cutaneous adnexal tumours derived from the hair shaft outer root sheath. We are reporting the first case of PTT in a young child. In this case, a 7-year-old girl presented with trichilemmal keratinisation consistent with PTT. The patient was monitored with no signs of recurrence. PTT is a rare tumour occurring primarily in adults and we present this case so that young patients with PTT can be diagnosed and treated appropriately with a painless, mobile, rapidly growing mass on the right upper eyelid. CT imaging showed well-circumscribed, heterogenous mass measuring 1.6 cm with fluid-filled appearance and no tissue invasion. Surgical excision was performed and pathology revealed an unencapsulated, well-demarcated tumour. © BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.