A case of lymphoid hyperplasia with prominent plasmacytic proliferation histologically and with polyclonal hypergammaglobulinemia and anemia clinically was reported. This condition in a 54-year-old Japanese male was probably a type of plasma cell dyscrasia similar to a plasma cell variant of Castleman's disease. About 19% of apparently nonatypical lymphocytes in the biopsy material of this case were found to have ribosome-lamella complexes (RLC) similar to those previously described in patients with hairy cell leukemia and some other hematologic disorders. An intimate association with the rough endoplasmic reticulum of these structures suggested aberrant protein synthesis by B-lymphocytes.