[Benign granular cell anal tumor].

INTRODUCTION: Granular cell tumors (GCT) are rarely located in the perianal area. OBSERVATION: Over the past 3 years, a 56 year-old man presented a papule of the right margin of the anus that had progressively increased in size (1.5 cm). Cell proliferation was located in the dermis and strongly expressed the S100 protein. It was covered by a pseudo-epitheliomatous hyperplasia of the overlying epidermis. Forty months after local surgical excision, there was no sign of recurrence. COMMENTS: Granular cell tumors are rare and usually benign. When cutaneous or mucosal, the pseudo-epitheliomatous hyperplasia of the overlying epithelium may, on superficial samples, be mistakenly diagnosed as squamous cell carcinomas. Malignant GCT may, histologically, appear identical to a benign GCT and only the appearance of metastases (generally after local recurrence) permits the subsequent diagnosis of malignancy.