OBJECTIVETo study the morphological and genetic characteristics in salivary gland marginal zone B cell lymphoma of mucosa associated lymphoid tissue (MALT) lymphomas.

METHODSTwenty-eight cases of MALT lymphomas of salivary gland were collected from Department of Pathology, Cancer Hospital of Fudan University. Morphological review based on HE sections, and specific chromosomal abnormalities were detected by two-color interphase fluorescent in situ hybridization (FISH). Four different probes were available to detect for API2-MALT1 fusion gene, bcl-10, IgH and MALT1 gene, respectively.

RESULTSThere were 16 females and 12 males, median age was 52. In those cases, 18 originated from parotid gland, 6 from submandibular and 4 from sublingual gland. Ten were localized mass and 18 were masses diffusely involved the glands. According to the clinical information, only 8 cases showed symptoms of dry mouth, dry nose or dry eye. Pathological findings showed that all cases had a dense lymphoid infiltration and obliteration and atrophy of acini and ducts. Twenty-two (78.6%) showed prominent monocytoid B cells and more often formed broad halos around epithelial islands. Eighteen (64.3%) showed clusters of lymphoblastic cells or plasma cells, Russel' and Dutcher' body were easily seen. Ten (35.7%) showed nerve or blood vessel infiltration. Interphase FISH showed that 3 cases harbored t(11;18) and 2 cases harbored trisomy 18, but none of all found IgH and bcl-10 translocations. After operation, 22 patients' follow-up information was available. One case died on 15 months later after operation, the rest of 21 cases were alive. Except surgical resection, patients did not get systematic radio-or chemotherapy. Eight to fifteen months after operation, 8 cases found recurred nodules on the original resected sites or cervical lymph nodes, but did not get repeated biopsy. All follow-up time was from 23 to 54 months.

CONCLUSIONSMost salivary MALT lymphomas are arising from parotid glands. Most patients do not have the symptoms of the Sjogren's syndrome. The final diagnosis depends on the pathological findings, the number and distribution of monocytoid B cells and clusters of plasmacytoid cells are hints for diagnosis of salivary MALT lymphomas, invasion of blood vessels or nerve also help for malignant diagnosis. t(11;18) and trisomy 18 may be the main chromosomal abnormalities in salivary gland MALT lymphomas, but with low morbidity. This genetic characteristic may connect with the low malignancy and slow progression in biological behavior.