Primary malignant lymphoma of the parotid gland

Objectives: To document the clinicopathologic features of primary malignant lymphoma of the parotid gland based on analysis of our cases and to compare the results with similar studies in the literature. Design: Retrospective, nonrandomized case study. Setting: Academic, tertiary medical center. Patients: Forty-one consecutive cases of malignant lymphomas of the parotid gland were identified among 820 patients who had undergone parotid surgery during the course of 22 years. Thirty-three (80%) of these were primary lymphomas and were included in the study. Eight (20%) occurred in patients with a history of malignant lymphoma and were therefore excluded. Intervention: Diagnosis was established by open parotid biopsy in 8 patients, superficial lobectomy in 23, and total parotidectomy in 2. After diagnosis, lymphomas were staged and treated with local irradiation and/or chemotherapy. Results: Fifteen men and 18 women aged 26 to 100 years (mean, 66 years) had an enlarging painless mass on initial examination. Seven (21%) had an underlying autoimmune disease and 20 (61%) had Ann Arbor stage I disease at diagnosis. Of 25 patients available for a minimum 2-year follow-up, 16 (64%) were alive with or without disease. Histological grade was the only prognostic feature associated with outcome (P<.01). Conclusions: Our study, when viewed collectively with those in the literature, indicates that malignant lymphomas of the parotid gland are uncommon and often not suspected clinically. The disease affects both sexes equally and is unusual before the age of 50 years. Most are B-cell, non-Hodgkin lymphomas, and about 80% of patients have Ann Arbor stage I or II disease at diagnosis.