Title: Extranodal MALT lymphoma in the oral cavity- a series of three cases with review of literature

Abstract

Background: Diagnosis of MALT (mucosa associated lymphoid tissue) lymphoma in the oral cavity is challenging. There is a great overlap in the histopathologic, immuno-histochemical and molecular features of MALT lymphoma with reactive lymphoid proliferations. The literature shows a very few case reports of primary MALT lymphoma of oral cavity. Methods: We discuss the histopathologic, immuno-histochemical, cytogenetic features, treatment, and behaviour of 3 cases of primary MALT lymphoma oral cavity along with review of literature. Results: The age ranged from 40 to 57 years (male to female ratio= 2:1). The sites involved were hard palate, bilateral gingivobuccal sulcus, and right buccal mucosa. The most common histology was centrocyte-like (2 cases). Lymphoepithelial lesions were absent. On immunohistochemistry, all tumours showed diffuse strong CD20 and bcl2 expression with strong and diffuse MNDA staining in one case. IgH; MALT1 translocation was not seen in any of these cases. One patient received local radiotherapy, one received steroids; while the case 3 received R-CHOP (Rituximab, cyclophosphamide, hydroxydaunorubicin hydrochloride, vincristine, and prednisone) chemotherapy. Two patients had complete remission while one had recurrence. Conclusion: MALT lymphoma of oral cavity shows a wide spectrum of morphology with presence of transformed cells, that may lead to misdiagnosis of diffuse large B cell lymphoma. The treatment guidelines are not well established but a tendency to excise MALT lymphomas of oral cavity has been observed. Nevertheless, MALT lymphoma of oral cavity appears to be an indolent disease.