Primary Malignant Lymphoma of the Parotid Gland in a Patient with Rheumatoid Arthritis.

Primary malignant lymphomas of the parotid gland are very rare. These neoplasms are believed to be associated with autoimmune disorders, such as Sjogren's syndrome. We present a case of primary malignant lymphoma in a patient with rheumatoid arthritis. A 69-year-old woman was referred because of right parotid gland enlargement. CT scans showed a right parotid tumor. We planned a superficial parotidectomy. However, the tumor gradually shrank and became impalpable in a month. Three months later, the patient was aware of right parotid gland enlargement again. CT scans showed another right parotid tumor. Examination of tissue obtained by fine-needle aspiration raised great suspicion of malignant lymphoma. A parotidectomy was performed. Histologic examination showed diffuse non-Hodgkin's lymphoma, mixed cell type. Postoperatively, the patient received radiotherapy and chemotherapy. One year after the operation, the patient is alive with no evidence of recurrence. The literature on primary malignant lymphoma of the parotid gland is reviewed.