Malignancy-simulating change in parotid gland oncocytoma following fine needle aspiration. Report of 3 cases

We report here three cases of benign parotid gland oncocytoma with pseudoma lignant change that mimic acinic cell carcinoma. All patients underwent fin e-needle aspiration biopsy of the tumor 62, 725 and 33 days before surgical excision. In histologic sections, there were clusters of pigmented cells w ith PAS-positive foamy to finely granular cytoplasm similar to those seen i n salivary gland acinic cell carcinomas. This report provides another, prev iously undescribed, example of a diagnostic pitfall that may be observed in histologic tissue specimens removed after FNA of oncocytic tumors.