Ribosome-lamellae complexes in benign plasma cells accompanying neoplastic infiltrates.

Two examples of ribosome-lamellae complexes (RLCs) occurring in benign plasma cells are presented. These were seen utilizing transmission electron microscopy in a case of mycosis fungoides in skin and a fibrosarcoma of a lower extremity. In both cases the accompanying plasmacytic infiltrate was interpreted as reactive and not malignant. Once thought to be a specific marker for hairy cell leukemia, RLCs now have been described in a wide variety of neoplastic diseases (mostly hematologic) and in a few examples of nonneoplastic conditions. RLCs have not been described previously in benign plasma cells. A review of the literature with respect to occurrence and significance of RLCs is presented.