University of Southern California (USC)
School of Dentistry Oral Pathology

Acinic Cell Adenocarcinoma

The acinic cell adenocarcinoma occurs mainly in the parotid gland, but intraoral and submandibular origin are also possible. This lesion is characterized by a benign histomorphologic picture but by occasional malignant behavior. These lesions are treated by surgical excision with a generous margin of normal tissue on the periphery. They do not tend to metastasize to lymph nodes but favor bone and lung as metastatic sites. They grow slowly and generally present with "benign" clinical features.

Acinic Cell Carcinoma Image #1
This photomicrograph illustrates the benign histomorphologic character of the tumor. It is termed acinic cell because the tumor cells show a marked similarity to the acinar cells of the normal gland. They have abundant purple cytoplasm and small dark uniform nuclei. Although they may appear to be benign microscopically, their clinical behavior is unpredictable, and even the most innocuous appearing lesions can metastasize.

Acinic Cell Carcinoma Image #2
This acinic cell adenocarcinoma has a slightly different microscopic picture with the presence of both vacuolated cells and acinar cells containing less granular cytoplasm than those in the previous frame.

Acinic Cell Carcinoma Image #3
This acinic cell adenocarcinoma shows a predominance of cuboidal cells with morphology similar to the intercalated ducts of the salivary gland.

Acinic Cell Carcinoma Image #4
Papillary cystic.

Acinic Cell Carcinoma Image #5
É and follicular are other patterns that may be seen in this often histologically variable tumor

Acinic Cell Carcinoma Image #6
This is an example of an acinic cell adenocarcinoma of the parotid gland. Notice the extensive involvement, the lobulated pattern and the vascular congestion of the skin. This actually is a recurrence of a lesion previously excised, and you can see the evidence of previous surgery below the mass. Microscopic examination showed a most innocuous appearing tumor with very uniform benign cells. However, the "proof of the pudding" is its clinical behavior. and certainly it is behaving in a most aggressive fashion. As in so many salivary gland tumors, the microscopic picture may not correlate well with the clinical behavior.