Immunoglobulin Crystals in Plasma Cell Leukemia

Author: Andrew Durkee, DO, 04/19/2022
Category: Lymphoma: Mature B-cell and Plasma cell Neoplasms > Plasma Cell Neoplasm > Plasma cell myeloma
Published Date: 04/20/2022

A patient with secondary plasma cell leukemia presented for re-induction therapy after increasing free light chain ratio. On admission plasma cell leukemia was confirmed with 49% peripheral plasma cells on flow cytometry. Further work up revealed elevated IgG to 10883 mg/L and M spike of 11.1 g/L. Review of peripheral blood revealed pancytopenia, plasma cells, rouleaux, and immunoglobulin crystals as shown. All crystals had a basophilic staining and found independent of other cells. The crystals were spread diffusely throughout the peripheral smear. This anomaly persisted for several days after the patient was started on Carfilzomib, Venetoclax and Dexamethasone before resolving. Immunoglobulin crystals are well described but uncommon finding in the peripheral blood. These crystals appear have a unique curved appearance.