Necrosis in benign salivary gland neoplasms. Not necessarily a sign of malignant transformation.

Necrosis that occurs in a salivary gland neoplasm is usually considered to be an ominous sign, suggesting malignant transformation, particularly in lesions that have had no prior manipulation such as fine-needle aspiration. We describe five pleomorphic adenomas and two canalicular adenomas of salivary gland origin that exhibited necrosis, yet were otherwise benign. All lesions displayed a distinctive histopathologic pattern characterized by a narrow rim of viable tumor tissue at the periphery of the neoplasm combined with a diffuse central region that demonstrated apparent ischemic necrosis. No invasion of adjacent normal tissue was identified, and no recurrence or metastasis has been seen with these lesions. Caution should be exercised in the evaluation of salivary gland neoplasms with central necrosis to avoid misdiagnosis of all such lesions as malignant.