Case report of a solitary fibrofolliculoma on the alar rim.

Fibrofolliculoma is a benign tumor characterized by a smooth, dome-shaped papule of size 2-4 mm. Most fibrofolliculomas occur as multiple lesions, and very rarely, they are solitary. Herein, we report a case of solitary fibrofolliculoma found in the alar rim, without the typical characteristics of a fibrofolliculoma. A 42-year-old man visited the hospital with a protruding lesion that had occurred 1 year previously. A mass of size 5× 7 mm was observed on the left alar rim. The tumor was dome-shaped and palpable. The patient did not have any similar lesions elsewhere. No family member was known to have such a lesion. An incisional biopsy was performed before surgery, and pathological examination revealed hyperkeratosis and dyskeratosis; however, an accurate diagnosis was not made. Complete resection was planned for the mass on the alar rim. The resected mass was subjected to permanent biopsy, and the pathological examination results led to the diagnosis of fibrofolliculoma. Therefore, when diagnosing a dome-shaped mass in the alar rim, despite the suspicion of a very rare disease, it is necessary to suspect fibrofolliculoma and consider the process from diagnostic examination to treatment.