Granular cell tumor is an uncommon, benign tumor that mainly occurs on the skin, tongue, and oral cavity as a single nodule. This tumor was previously thought to be derived from muscle by Abrikossoff and was called as “granular cell myoblastoma.” Recent ultrastructural studies and stains such as S100 and neuron-specific enolase confirm that this tumor is derived from Schwann cells of the peripheral nerves.

A 48-year-old male patient was admitted to our hospital with the complaint of expanding mass in his left lumbar region for about 5five months. On his dermatological examination, a 5 x 4 cm sized, pink-–brown tumor was detected in his left lumbar region. The tumor was hard on palpation. There was an ulcer 1 cm in diameter at its center. The borders of the tumor were regular. On histopathological examination, pseudoepitheliomatous hyperplasia in the epidermis and tumoral infiltration in the dermis were detected; the infiltration was composed of cells with large eosinophilic cytoplasm containing fine granules and numerous oval-–round nuclei. Cytoplasmic granules stained positive with PAS and S100 stain. Granular cell tumor was diagnosed on the basis of clinical and histopathological features.

The clinical diagnosis of granular cell tumor is difficult and depends on the histopathological findings. Outside of the typical region of involvement, as observed in our case, any region can be involved. Granular cell tumor is a benign neoplasm with good prognosis. A tumor larger than 4 cm in diameter, the presence of ulceration, rapid growth, and lymphadenopathies are signs that suggest malignancy. Although in our case the lesion was greater than 4 cm in diameter, there was ulceration, and rapid growth, the histopathological features were benign. No recurrence was observed for 13 months in its pursuits after wide local excision.

Keywords: Granular cell tumor, lumbar region, ulcer