Basal cell adenoma in the parotid gland: CT and MR findings.
(51) Alterations in benign tumors, such as pleomorphic adenoma and
basal cell adenoma, may be retained in their malignant counterparts.
Two cases of
basal cell adenoma were seen involving the parotid gland (1.75%).
Solid-type adenoid cystic carcinoma, cutaneous basal cell carcinoma,
basal cell adenoma, and small cell carcinoma should all be taken into consideration for differential diagnosis (3, 7, 8).
Pathological diagnosis was obtained: schwannomas (8 cases), salivary pleomorphic adenomas (5 cases), angiomas (5 cases), branchial cysts (3 cases), Castleman disease (2 cases), and 1 case for each of the followings: lymphoepithelial cysts, thyroid cancer lymphatic metastasis, phosphate urinary mesenchymal tissue tumor,
basal cell adenoma, myoepithelial carcinoma, fibroma, adenoid cystic carcinoma, and lipoma.
The pathology differential diagnosis includes polymorphous low-grade adenocarcinoma, pleomorphic adenoma,
basal cell adenoma, basal cell adenocarcinoma, epithelial-myoepithelial carcinoma, basaloid squamous cell carcinoma, neuroendocrine carcinoma, and even sialoblastoma.
Basal cell adenoma (BCA) is a benign salivary gland tumor that most frequently arises in the parotid gland and is characterized by the basaloid appearance of the tumor cells and the absence of the myxochondroid stromal component present in pleomorphic adenoma.
Other less common benign SGT's in our study included 1 case (0.62%) each of
Basal cell adenoma, myoepithelioma, oncocytoma, sebaceous lymphadenoma and Haemangioma respectively.
Histologically, trabecular type of
basal cell adenoma, pleomorphic adenoma and polymorphous low-grade adenocarcinoma should be discriminated from canalicular adenomas.
Radiologically it is difficult to distinguish pleomorphic adenoma from its variants, myoepithelioma and
basal cell adenoma. (14) Imaging techniques ultrasound, magnetic resonance (MRI), or computed tomography for diagnosis of salivary gland tumour depends on the site & size of the tumor.
An example includes a tumor of basaloid morphology, for which the differential diagnoses include
basal cell adenoma, basal cell adenocarcinoma, and adenoid cystic carcinoma.
In such cases, differentiating the
basal cell adenoma and polymorphous low-grade adenocarcinoma becomes difficult.