A case of coincident multiple myeloma and non-Hodgkin's lymphoma.

A rare case of coexisting multiple myeloma and non-Hodgkin's lymphoma at the time of diagnosis is presented. The patient presented with petechiae, melena and weight loss. IgA lambda monoclonal gammopathy in the serum and free lambda chain in urine were documented. Bone marrow biopsy demonstrated an interstitial infiltration of neoplastic plasma cells coexisting with localized collection of neoplastic lymphoid cells composed of monotonous small lymphocytes with occasional cleaved nuclei. Immunophenotype of plasma cell was IgA lambda. The patient also had a jejunal mass, with biopsy proven malignant lymphoma, diffuse small cleaved cell type. The tumor was diffusely positive for pan-B marker. After chemotherapy, the IgA lambda monoclonal protein decreased and the patient improved. This case suggest, that the seound B-cell neoplasm may have evolved by transformation of an original neoplastic clone, or that malignant tumors may be polyclonal at onset. Definitive diagnosis and staging of each disorder is important for proper management.