Acinic Cell Carcinoma of Minor Salivary Glands: A Clinicopathologic Study of 21 Cases

Abstract

Acinic cell carcinoma (ACC) is an infrequent type of malignant salivary gland tumor. Approximately 16% of all ACCs occur in the mouth according to several small studies. This study was undertaken to 1) report on the clinicopathologic characteristics of 21 intraoral examples, 2) reconfirm the reported indolent behavior of these tumors, and 3) verify the synchronous or metachronous occurrence of other malignancies with ACC. Twenty-one patients with intraoral ACC were identified in the previous 27 years. Demographic data and histomorphologic characteristics were evaluated and follow-up information was sought. Fifteen patients (68%) were male and 6 female. Seven cases (33.3%) occurred in the buccal mucosa, 6 in the palate (28.6%), 5 involved the upper lip (23.8%), 2 the retromolar mucosa (9.5%), and 1 the lower lip (4.8%). The mean age of patients was 50 years, with the youngest being 13 and the oldest 73. The duration was known in 9 patients and varied from 4 months to longer than 15 years. The size of the tumors varied from 0.6 to 1.6 cm. Where reported, lesions were asymptomatic. Histologically, different patterns that included microcystic, papillary cystic, follicular and solid, and combinations of these types characterized the lesions. Follow-up information was obtained in 12 patients. Eleven patients did not report recurrence or metastatic disease. The follow-up extended from 10 months to 17 years. One patient had 2 recurrences due to erroneous diagnosis that led to inappropriate treatment. After properly diagnosed and treated, this patient has been free of tumor for 4 years. Of interest were the metachronous occurrence of lymphoma in 1 patient and the synchronous occurrence of renal cell carcinoma in another. This study confirms the indolent behavior of ACC of minor salivary glands and previous reports on the occasional synchronous or metachronous association of malignant salivary gland tumors with other malignancies.