Abstract
Background : Oncocytic carcinoma of the salivary gland is a very rare malignant epithelial tumor. We report a patient with oncocytic carcinoma of the submandibular gland, mainly focusing on the findings on aspiration cytology.
Case : A 55-year-old male noticed a mass in the right submandibular area 1 year earlier and visited our hospital when he noted an increase in its size. A submandibular fine-needle aspiration cytology revealed many irregularly scattered cell clusters in the tumor. The background was clear, and the cell arrangement lacked polarity. The cells contained abundant granular cytoplasm and showed unclear borders. The nuclei were large and round and showed marked anisokaryosis and hyperchromasia, with single large nucleoli. These findings were suggestive of the diagnosis of oncocytic carcinoma. Histology of the surgical specimen revealed proliferation of the tumor cells in solid sheets, the cells containing eosinophilic granular cytoplasm. The tumor cells were pleomorphic, with large atypical nuclei. The tumor lacked a fibrous capsule, and the tumor cells infiltrated the soft tissues around the submandibular gland, with prominent perineural invasion. Phosphotungstic acid-hematoxylin (PTAH) staining revealed dark-blue granules in the cytoplasm, and immunostaining for antimitochondrial antibody was positive. Based on these findings, a diagnosis of oncocytic carcinoma was made.
Conclusion : The cytodiagnosis of high-grade oncocytic carcinoma is possible if careful attention in paid to the cellular atypia and the characteristic granular cytoplasm.
