Abstract: Extranodular marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a distinct subgroup of non-Hodgkin's lymphoma, with a particular clinicopathologic behavior. It is one of the most common types of extranodular low-grade B cell lymphoma. Stomach is the most common site of MALT lymphoma. The typical MALT is an indolent lesion that usually remains localized for a long period and often grows slowly. In our study, the extranodular marginal zone B-cell lymphoma lesions occurred in the tonsils, progressed rapidly with B-cell lymphoma symptoms, and the clinical manifestation did not correspond with the pathologic features. Efforts at making an accurate prognosis for MALT lymphoma by molecular pathology are worthwhile for further investigation.