Spontaneous infarction of pleomorphic adenoma: report of a case simulating malignancy on fine-needle cytology sample

Ischemic or hemorrhagic infarction has been described as an uncommon but possible complication of fine-needle cytology sampling in numerous organs, more frequently the thyroid, the salivary glands, the breast, the lymph node, and the kidney. In these situations, infarction appears to be directly related to the vascular disturbances caused by needle sampling, though fine this latter might be. One case of a spontaneous infarction of a parotid pleomorphic adenoma in a 46-year-old lady is here described in which the cytopathologic findings, which were related to ischemic infarction, preceded fine-needle cytology sampling and mimicked malignancy. The cytopathologic picture showed a quizzical mixture of necrosis and inflammation coupled to hyperplastic changes of the acinar cells, oncocytic metaplasia, and atypical squamous metaplasia of extreme degree simulating high-grade epidermoid- or mucoepidermoid carcinoma. Due to the cytologically suggestive changes, a nerve-sparing radical parotidectomy was performed. The differential diagnostic problems encountered in this case are discussed together to the possible medical-legal implications originating from such striking atypias as to closely simulate malignancy.