MYD88 L265P somatic mutation: its usefulness in the differential diagnosis of bone marrow involvement by B-cell lymphoproliferative disorders.

[waldenstrÃ¶m macroglobulinemia]

To examine the usefulness of the MYD 88 L 265 P somatic mutation in identifying cases of lymphoplasmacytic lymphoma (LPL ) from other lymphoplasmacytic neoplasms in bone marrow biopsy specimens .We studied 64 bone marrow biopsy specimens with involvement by various small B-cell lymphomas or plasma cell myeloma .The MYD 88 L 265 P somatic mutation was present in 13 /13 cases of LPL , 1 /13 cases of hairy cell leukemia , and absent in the other mature B-cell neoplasms tested . A test set of diagnostically challenging bone marrow cases with lymphoplasmacytoid morphology (B-cell lymphoma , not otherwise specified ) was selected for additional review and reclassified , without knowledge of the MYD 88 L 265 P status . Of those 16 cases , 7 were positive for MYD 88 , including 4 /4 cases that were reclassified as LPL during the review .Although not entirely specific , MYD 88 L 265 P is a useful adjunct for bone marrow diagnosis in separating LPL from other small B-cell lymphomas and plasma cell myeloma .