Proliferating tricholemmal tumour: clinicopathological aspects of a case

Khoja AA, Yan B, Lee SJ, Cheong EC, Tan KB
Correspondence: Dr Kong-Bing Tan, pattankb@nus.edu.sg

ABSTRACT
We report the case of a 49-year-old man who presented with an enlarging mass over his occipital scalp. The clinical impression was either a squamous cell carcinoma or an unusual adnexal tumour. A wide excision was performed with skin grafting. Gross examination revealed
a large exophytic tumour mass measuring 10 cm. Histopathological examination showed a circumscribed, well-differentiated squamoproliferative lesion with a lobulated architecture. Clear cell features, pilar-type keratinisation, microcalcifications and the presence of mucinous degeneration were noted. A diagnosis of proliferating tricholemmal tumour was made. This entity incorporates a spectrum of lesions, ranging from the mostly benign proliferating tricholemmal cyst to tumours having more atypical cellular and invasive features, the latter features correlating with an increased capacity for aggressive behaviour. Management-wise, such tumours require complete excision with follow-up. As the tumours are often large in size at presentation, reconstruction is required.

Keywords: adnexal and skin appendage neoplasms, pillar cyst, reconstructive surgical procedures, skin neoplasms
Singapore Med J 2011; 52(12): e255-e257