Posttraumatic giant proliferating trichilemmal cysts on the parietal region of the scalp.

Proliferating trichilemmal (pilar) cysts, also known as pilar tumors, are most commonly found on the scalp of elderly women. Proliferating trichilemmal cysts are rare, slowly growing, lobular masses inherited autosomal dominantly and localized on scalps, and believed to arise due to a complication of a trauma and inflammation, and 5-10% of people are reported to be effected. Herein, we present the case of a 70-year-old woman with a 23-year history of multiple enlarging scalp masses. Clinically, squamous cell carcinoma was considered in the differential diagnosis, and the lesion was totally excised. Our case emphasizes the necessity for detailed clinical and pathological correlation for differential diagnosis.