[Granular cell tumor]

Eighteen granular cell tumors (GTC) were detected from January 1976 until September 1988. GTC is found in 0.03% of all the biopsy specimens. Women have been found to be affected more frequently. The most common anatomic sites where it appears are the skin and subcutaneous tissue of the trunk and the vulva. Tumors ranged in sizes from 0.6 to 4 cm (average 1.5 cm). One patient had multiple lesions. The lesions show typical histologic features, usually with ill-defined edges. The preoperative diagnoses were never determined as GTC. Pseudoepitheliomatous hyperplasia of the overlying epithelium led to the wrong intraoperative diagnosis of squamous cell carcinoma in one lingual GTC. On gross inspection, one breast GTC was mistaken for invasive carcinoma with desmoplasia. One vulvar lesion was previously diagnosed as pseudo-decidual reaction. Malignant behaviour could not have been noticed, since it is of importance to pathologists and clinicians not to misinterpret this lesion as carcinoma.