Diagnosis of a case of thymus area lymphoma

This was a rare case, in which clinical manifestation was a thymus area tumor accompanied by proteinuria, kidney dysfunction and kidney enlargement. Tumor biopsy and bone marrow examination failed to clarify its diagnosis. Renal biopsy revealed diffuse infiltration by atypical lymphoid cells in renal interstitium. Immunoperoxidase studies demonstrated this case was non-Hodgkin's lymphoma (NHL) of the B cell type through the renal biopsy.