To investigate the incidence of MALT-lymphoma in Sjogren's disease by means of biopsy of the enlarged parotid glands.
The incisional parotid biopsy was performed in 57 primary Sjogren's syndrome (pSS) patients with existing parotid enlargement. The median age was 54 years (range 19-75 years). The median pSS duration was 7 years (range 1-30 years). The palpable parotid enlargement was defined as grade 1 and massive (visional) enlargement of the parotid glands was defined as grade 2. Histologic and immunohistochemical examinations for diagnosis of lymphoma were made. High resolution electrophoresis and immunofixation were performed for detection of monoclonal immunoglobulins in the serum and their free light chains in the urine.
Biopsy of the enlarged parotid glands identified MALT-lymphoma in 37 of 57 (64.9%) pSS patients. Of 37 pSS patients with parotid enlargement of grade 2, diagnosis of MALT-lymphoma was made in 89.2%. Of 20 pSS patients who had parotid enlargement of grade 1, MALT-lymphoma was diagnosed in 20%. In patients with grade 1 enlarged parotid glands MALT-lymphoma was identified only in cases with the presence of monoclonal immunoglobulins in the serum and their free light chains in the urine (3 of 4 patients) or in case of disseminated disease (lymphoma involved regional lymph nodes and soft tissues of the face)--1 of 4 patients. In patients with grade 2 enlargement of parotid glands MALT-lymphoma located most frequently in affected parotid glands (69.6%).
The incisional biopsy of enlarged parotid glands is necessary for detection of MALT lymphoma in pSS patients.