Salivary duct carcinoma of the parotid gland: report of a rare case with a comparative study of aspiration cytology and histomorphology.

BACKGROUND

Salivary duct carcinomas affecting primarily the parotid gland are extremely rare (0.2-2% of all salivary gland tumors). These carcinomas are considered to be of high grade malignancy, with mortality in up to 70% of cases. They usually affect elderly males and less often young adults. Despite the fact that the histomorphologic characteristics of this tumor are always necessary for its classification, several authors have reported that the cytopathologic approach, using fine needle aspiration (FNA) cytology, can establish the final diagnosis. The aim of this paper is to present a rare case of salivary duct carcinoma of the parotid gland with no typical microscopic findings that was diagnosed by FNA cytology through a combination of techniques on biopsy material.

CASE

A 56-year-old male presented with a right parotid mass measuring 6 cm in diameter. The mass appeared to expand subcutaneously and infiltrate the skin of the neck region. Biopsy material from both the mass and skin was obtained using FNA and processed with conventional, cell block and liquid-based cytology techniques. A core biopsy was also performed on the mass for histologic evaluation.

CONCLUSION

The findings were consistent with a salivary duct carcinoma of the parotid gland and were confirmed by the histologic report. FNA cytology combined with such techniques as liquid-based cytology provides the potential for the final diagnosis. Liquid-based cytology can improve the cellular morphology of the material and allows immunocytochemistry and other diagnostic techniques. The application of such techniques is significantly restricted by conventional processing; thus, combining liquid-based cytology with other techniques expands the boundaries of cytology as a diagnostic test.