Basal cell adenoma in the deep portion of the parotid gland: a case report

Abstract

Basal cell adenoma (BCA) is a rare, benign neoplasm that most frequently arises in the parotid gland. We treated a 54-year-old female patient with BCA that had developed in the deep portion of the left parotid gland. The patient presented with gradual facial swelling with no other symptoms. We performed a total parotidectomy to excise the mass, but we preserved the facial nerve. Histopathology revealed a well-encapsulated mass. The tumor was composed of islands of comparatively uniform, small, dark, basaloid epithelial cells in the stroma. Histologic and immunohistochemical studies concluded that the BCA tumors were mostly trabecular. Postoperatively, there was no facial nerve weakness, and the tumor did not recur during the 24-month follow-up period.

Keywords: Basal cell adenoma; Facial nerve preservation; Parotid gland.

Fig. 1. Computed tomography scan; 1.7×1.5 cm sized well-encapsulated enhancing mass on left parotid gland. A. Axial. B. Coronal.

Fig. 2. Incision design has been made. Dotted line, swelled region; narrow line, incision line; wide line, contour of angle of mandible.

Fig. 3. A. The superficial part of the parotid gland has been excised. B. Excision of tumor with preserving the facial nerve and the branches. C. Excised tumor. D. The facial nerve and the branches have been preserved.

Fig. 4. A. Fibrous capsule of the tumor is surrounding trabecular tumor cell nests (H&E staining, ×40). B. Trabecular tumor cells and tumor cell nest formation (H&E staining, ×200). C. The basal cells are expressed by p63 (immunohistochemical staining, ×200). D. The luminal cells of tubular structure are stained by HMK-CK (immunohistochemical staining, ×200).