Sebaceous lymphadenocarcinoma of salivary glands.

Primary sebaceous neoplasms of the salivary glands are extremely rare occurrences; furthermore, sebaceous lymphadenocarcinoma has only been reported in three patients. We report a case of sebaceous lymphadenocarcinoma arising in a lymphadenoma of the parotid gland. The patient was a 55-year-old man who presented with a parotid mass of 3 years' duration. Histologically, the lesion consisted of a sebaceous lymphadenoma with transition to a sebaceous carcinoma. The cytologic touch-preparation at the time of frozen section showed clusters of benign sebaceous cells in a rich lymphocytic background together with tridimensional clusters of malignant epithelial cells, strongly raising the suspicion of a malignant neoplasm arising in a benign sebaceous lesion. Malignant transformation of the sebaceous lymphadenoma, although rare, should be considered in enlarging, locally invasive parotid lesions, considering that clinical behavior and prognosis will be determined by the nature of the malignant component.