Granular cell tumor of the penis shaft: case report and literature review

Introduction: Granular cell tumors ( GCT) are uncommon soft tissue neoplasms of presumed neural origin that rarely involve the male external genitalia. Penile lesions are distinctly uncommon with less than 20 cases reported till now. Objective: In the present paper we describe the clinicopathological and immunohistochemical findings in a case of GCT of the penis shaft in a 31 years old man. Results and Conclusions: On physical examination the patient was found to have a small ovoid mass, 20 x 10 mm in diameter, at the left postero-lateral area of the penis' base. The mass was firm on palpation with no fixation on the neighboring tissues. The lesion was completely excised under loco-regional anesthesia. The surgical specimen was an ovoid, gray-white, elastic mass, of 10 x 5 mm. Microscopically, the tumor was moderately cellular and was composed of polygonal-shaped cells with abundant granular eosinophilic cytoplasm. Tumor cells were disposed in nests, cords, and trabeculae and showed perineural invasion. The tumor presented bland cytological features with only focal slight nucleomegaly. Mitotic activity was undetectable. The tumor cells showed diffuse immunohistochemical expression for S100 protein. At 6 month after surgery the patient was free of persistent/recurrent disease or metastatic spread of the tumor. We discuss the clinical, histo-immunohistochemical and therapeutical features of this unusual penile tumor, the single one encountered in the Department of Pathology from Timisoara County Hospital and, to our knowledge, the only one reported in the Romanian medical literature.