Acinic cell carcinoma: long-term survival after pulmonary metastases: light and electron microscopic study

Metastatic pulmonary nodules discovered 6 years after superficial parotidectomy for an acinic cell carcinoma in a 61-year-old man were studied by light and electron microscopy. The lesions were composed of clear cells and darker, gland-forming cells with granular cytoplasm, which by electron microscopy demonstrated features of ductal and acinar serous cells, respectively. Cytologic evidence of malignancy, such as extensive necrosis, nuclear pleomorphism, significant mitotic activity, incomplete encapsulation, and perineural invasion was present. The patient is free of tumor 5 years after resection of the pulmonary lesions. In view of the indolent growth characteristics of this tumor, a more aggressive surgical approach to metastatic tumor foci is recommended.