Basal cell adenoma is a benign epithelial tumor of the salivary glands. Klein sasser and Klein (1967) first described its pathological features and classified it as a type of salivary gland tumor. Evans (1970) further elaborated on its characteristics. The tissue origin of basal cell adenoma is the intercalated duct cells or reserve cells.

bubble_chart Pathological Changes

1. Gross morphology Basal cell adenoma appears round or oval, with a smooth surface, complete encapsulation, and clear boundaries from surrounding tissues. The tumor is generally small in size. The cut surface is mostly solid and grayish-white, but cystic changes may occur, presenting as varying-sized cystic cavities containing thin, brownish-red mucoid material.

2. Microscopic examination The tumor consists of neoplastic epithelial cells and a small amount of connective tissue. The tumor cells are densely packed into clusters or cords, appearing round, oval, or spindle-shaped, with scant basophilic cytoplasm, round and deeply stained nuclei, and inconspicuous nucleoli. Sometimes, the peripheral areas of the epithelial clusters are arranged in a single layer, resembling basal cell carcinoma of the skin, but mitotic figures are rare. The tumor lacks myoepithelial cells, and the boundary between the tumor parenchyma and stroma is clear, separated by a basement membrane. In some cases, varying-sized cystic cavities may appear within the epithelial clusters, filled with degenerated tumor cells. The stroma consists of fibrous connective tissue with minimal mucin content.

3. Biological characteristics Basal cell adenoma grows slowly, has a complete capsule, and postoperative recurrence is relatively rare.

Basal cell adenoma accounts for about 2% of salivary gland tumors, most commonly occurring in the parotid gland among the major salivary glands, and in the upper lip among the minor salivary glands. It is more common in male patients, rare in those under 40 years old, and most frequently occurs between the ages of 50 and 60.

The tumor grows slowly, has a long course, and presents no subjective symptoms, often leading to medical consultation due to a painless mass. The tumor has clear boundaries, is not adherent to surrounding tissues, and is mobile. It is mostly round or oval in shape with a soft texture.

Sialography X-ray findings show space-occupying changes characteristic of benign tumors.

bubble_chart Treatment Measures

The method of surgical resection is adopted, but simple surgical resection is inappropriate; at least the normal tissue outside the tumor should be removed.