A case of parotid gland secretory carcinoma detected and treated in the state of advanced cancer

Abstract

Background : Parotid gland secretory carcinoma is a low-grade tumor, and distant metastasis from this tumor is rare.

Case : The patient was a male in his 60 s. Computed Tomography showed a 40-mm-sized cervical mass around the lower pole of the left parotid gland and a 14-mm-sized right visceral pleural mass with effusion, suggesting the possibility of cervical lymph node metastasis from lung cancer. Fine-needle aspiration cytology (FNAC) of the left cervical mass showed tumor cells with oval nuclei and nuclear grooves arranged in sheets or in a partially papillary manner. The cytoplasm was relatively abundant and vacuoles were conspicuous. Secretory material showing focal metachromasia on Giemsa staining suggested the possibility of parotid gland secretory carcinoma. Immunohistochemical staining of the biopsy specimen showed diffusely positive reaction for S-100 protein, and partially positive reaction for mammaglobin. FISH revealed a positive result for the ETV6/NTRK3 break-apart signal, which led to the final diagnosis of parotid gland secretory carcinoma. Immunohistochemical staining of the cell block prepared from the right pleural fluid showed generally similar staining results as the cervical mass biopsy, and the patient was diagnosed as having pleural metastasis from a parotid gland secretory carcinoma.

Conclusion : Irrespective of the initial clinical diagnosis, careful analysis of the FNAC specimen, with further confirmation by FISH led us to make the final diagnosis of parotid gland secretory carcinoma. Following the diagnosis, the treatment proceeded smoothly under the supervision of a team of clinicians, pathologists, and cytotechnologists.