Basal cell adenoma of the parotid gland: Cytological diagnosis of an uncommon tumor

Abstract

Basal cell adenoma (BCA) is a rare benign epithelial tumor of the salivary gland, displaying monomorphic basaloid cells without a myxochondroid component, representing 1–3% of all salivary gland neoplasms seen predominantly in women over 50 years of age. It is uncommon in young adults. Cytodiagnosis of basaloid tumors chiefly basal cell adenoma of the salivary gland, is extremely challenging. The cytological differential diagnoses range from benign to malignant, neoplastic to non- neoplastic lesions. Histopathological examination is a must for definitive diagnosis, as these entities differ in prognosis and therapeutic aspects. We present a 22-years-old male with this uncommon diagnosis with a discussion on the role of cytological diagnosis. Fine needle aspiration cytology is a simple, minimally invasive method for the preoperative diagnosis of various types of neoplastic and non-neoplastic lesions. The knowledge of its pitfalls and limitations contributes to a more effective approach to treatment.

Potential Difficulties in Cytological Approach of Basal Cell Adenoma of Salivary Glands: The Experience of a Single Institution

“…However, as previously stated, due to therapeutic and prognostic implications, the most important entities that must be differentiated from BCA in a FNAC procedure are basal cell adenocarcinoma and adenoid cystic carcinoma [2].…”

“…Canalicular adenoma should be kept in mind for its cytological features even if it occurs almost exclusively on the upper lip: it is characterized by small, regular cells and nuclei arranged in a trabecular or tubular pattern [2].…”

“…The majority of them are benign, and approximately 80% originate in the parotid gland. Basal cell adenoma (BCA) is an uncommon benign salivary gland tumor accounting for 1-2% of all salivary gland epithelial tumors [2,3]. It affects most frequently adult patients over 50 years of age with slight female prevalence.…”

Synchronous Ipsilateral Parotid Tumors with Cytologic–Histologic Correlation

“…Cytologically, sheets of small basaloid cells containing oval nuclei with fine chromatin that are usually devoid of prominent nucleoli are seen [6,7]. However, histopathologic confirmation of basal cell adenoma is necessary in order to exclude potential benign and malignant mimickers, including basal cell adenocarcinoma, canalicular adenoma, cellular pleomorphic adenoma, and the solid variant of adenoid cystic carcinoma [8]. Histologically, this tumor type is composed of nests of uniform basaloid cells, often displaying peripheral palisading, separated by a collagenous stroma [5,8].…”

“…However, histopathologic confirmation of basal cell adenoma is necessary in order to exclude potential benign and malignant mimickers, including basal cell adenocarcinoma, canalicular adenoma, cellular pleomorphic adenoma, and the solid variant of adenoid cystic carcinoma [8]. Histologically, this tumor type is composed of nests of uniform basaloid cells, often displaying peripheral palisading, separated by a collagenous stroma [5,8]. The membranous variant is further distinguished by the presence of prominent, hyalinized basement membrane-like material [5].…”