Cytoplasmic fibrils in plasma cell leukemia.

In a patient with plasma cell leukemia, associated with pleural effusion, ultrastructural studies of the peripheral blood plasma cells showed an abundance of cytoplasmic fibrils. The nature of fibrils was not clarified, but they were not amyloid fibrils. This finding, coupled with a liaterature review, suggests that the cytoplasmic fibrils in plasma cells may be an additional cytological feature of this rare form of leukemia.