Primary sublingual gland marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type: A case report

Mucosa-associated lymphoid tissue (MALT) lymphoma arising in the sublingual gland of the oral cavity is very rare. We present here a single case of MALT lymphoma arising from the sublingual gland of a 64-year-old man. His first symptom was swelling on the left side of the floor of the mouth. On the basis of the results of imaging studies, a salivary gland tumor was suspected. The tumor was dissected surgically and microscopically, revealing dense atypical lymphoid cell infiltration with severe destruction of adjacent normal salivary glands. Immunohistochemical staining of atypical lymphoid cells was positive for CD20 and CD79a. Ki-67 positive cells were localized to scattered transformed large cells. As a result, the tumor was diagnosed as a primary sublingual gland marginal zone B cell lymphoma of MALT type.