Gastric MALT Lymphoma with Biclonal Gammopathy and Bone Marrow Involvement Mimicking Multiple Myeloma.

Mucosa-associated lymphoid tissue (MALT) lymphomas are B-cell neoplasms that commonly affect the gastrointestinal (GI) tract, usually the stomach. In most cases, extranodal marginal zone lymphoma (ENMZL) is an indolent disease. Bone marrow involvement is common with MALT lymphoma accompanied by paraproteinemia; such involvement impels disease progression.