Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade lymphoma arising not only in the stomach, but also in various nongastrointestinal sites. Clinically, MALT lymphoma behaves as an indolent disease with a prolonged clinical course, and it rarely occurs in the oral cavity. We report a case of MALT lymphoma simultaneously occurring in the palate and the right parotid gland of a 61-year-old woman.
18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been shown to be useful for the evaluation of most types of lymphomas. However, whether FDG-PET is useful for the staging of MALT lymphoma remains controversial, because false-negative cases of low-grade malignancy have been reported. In our patient with biopsy-proven MALT lymphoma, FDG-PET revealed avid accumulation of FDG in both lesions and the right cervical lymph nodes. MALT lymphoma of stage II E was diagnosed, since no other tumor dissemination was evident. All lesions were successfully treated (complete remission) with 30 Gy of radiation therapy. There have been no signs of recurrence 18 months after treatment. The palate lesion had a higher maximum standardized uptake value (SUVmax) of 10.3 and showed more MIB-1 positive cells than the parotid lesion (SUVmax: 3.8), associated with less proliferation.
