Selected topics in salivary gland tumour pathology

Adenoid cystic carcinoma of the parotid gland

Adenoid cystic carcinoma (ACC) is a slowly progressing malignant tumor of the salivary glands that mostly affects minor salivary glands. ACC of parotid gland is exceptionally rare. In this article, we aimed to provide a case report of parotid gland ACC in a 55-year-old female that was misdiagnosed as benign mixed tumor. The patient was successfully treated by surgery without any complications. We recommend that ACC of parotid gland should be considered in differential diagnosis of benign mixed tumor since there still existed overlapped imaging characteristics.

A rare case report of adenoid cystic carcinoma of parotid gland with perivascular and perineural spread

Adenoid cystic carcinoma is a slow growing malignant neoplasm of the salivary glands, mainly occurring in minor salivary glands and relatively rare in parotid glands. It has got a remarkable capacity for extensive subclinical spread to the adjacent structures. Here, we present a case report of adenoid cystic carcinoma of parotid gland with perineural and perivascular spread. To our knowledge, this is the first reported case of adenoid cystic carcinoma of parotid gland with perivascular spread along a major artery (ECA) and perineural spread along two different nerves (mandibular nerve and facial nerve)

Detection of claudin-4 in salivary gland neoplasms (a study utilizing RT-PCR and immunohistochemistry)

BACKGROUND

Claudins are transmembrane proteins of tight junctions emerging as targets for diagnosis, prediction of prognosis, disease recurrence, and metastasis. Our goal was to evaluate expression of claudin-4 in the most common benign and malignant salivary gland neoplasms.

METHODS

Claudin-4 gene levels and protein expression were determined by real-time polymerase chain reaction (PCR), and immunohistochemistry in a total of 30 specimens containing normal salivary tissue, pleomorphic adenoma, Warthin's tumor, mucoepidermoid carcinoma, and adenoid cystic carcinoma.

RESULTS

We identified down-regulation of claudin-4 gene levels and protein expression from normal control to benign salivary gland neoplasms and reached their lowest values in the malignant salivary gland neoplasms.

CONCLUSIONS

Low claudin-4 expression could be considered as a sign of increasing cellular disorientation and invasion of salivary gland tumors.

Adenoid cystic carcinoma ex pleomorphic adenoma of the parotid gland

There is a considerable variation in the histologic subtype of epithelial malignancies among carcinoma ex pleomorphic adenomas (CXPA) and virtually any known carcinoma entity can develop. To our knowledge, adenoid cystic carcinoma (AdCC) ex PA is quite rare despite the fact that de novo AdCC is the fourth most common salivary gland malignancy. We describe a new case of AdCC ex PA in the parotid gland of a 62 year-old woman. In our patient, there was a short interval of time between parotidectomy and local recurrence and rapid development of distant metastases. Although most of the reported cases are considered low-grade, evidence is presented here that AdCC can take the form of a high-grade malignancy in PA.

Cytokeratin profile in mucoepidermoid carcinoma is not related to its histological grading of malignancy

The objective of this experiment was to determine the relationship between the expression of cytokeratins (CKs) and histologic grading in MEC. Eleven cases of MEC were selected and graded as low, intermediate and high-grade tumors. The expression of CKs 7, 8, 10, 13 and 14 was assessed immunohistochemically using streptavidin-biotin complex method. The results showed that the studied CKs were expressed in most cases of MEC, independently of histologic grading. Nonetheless, low-grade tumors demonstrated intense staining of CK 7 and 8; additionally, CK 10 and 13 were more pronounced in this grade. The immunoexpression was variable according to cellular type and organization pattern of the tumor. Mucous cells were positive for CK 7 and 8; epidermoid cells were stained for CK 10, 13 and 14; CK 7, 8, 10 and 14 were observed in intermediate cells, and CK 7 was occasionally seen in clear cells. Cystic structures and duct-like elements in MEC were positive for CK 7 and 8, whereas solid nests showed positivity for all CKs. These results suggest that expression profile of these proteins does not reflect the biological behavior of MCE, however, it guides the detection of cellular types and differential diagnosis from other salivary gland tumors.

Adenoid cystic carcinoma of the parotid metastasizing to liver: case report

Background

Adenoid cystic carcinoma is a rare malignant parotid tumor. Metastasis can occur even a decade or more after initial treatment of the primary.

Case presentation

We report a 60 year old female patient who presented with adenoid cystic carcinoma of the parotid gland. She underwent a total conservative parotidectomy followed by adjuvant radiotherapy. While on follow up, patient developed multiple liver metastases which manifested three years later. Patient lived for another two years before she died of her disease.

Conclusions

Although distant metastases of adenoid cystic carcinoma develop frequently, isolated metastasis to liver is unusual. Even after manifestation of distant metastasis, patients can be expected to live for a number of years. Palliative chemotherapy can be considered in symptomatic cases while the usefulness of metastatectomy is controversial.