Hemoglobin: 97 g/dL
WBC: 11.2 x 10e9/L
Platelets: 178 x 10e9L
Mean Corpuscle Volume (MCV): 97.2 fL
Flow cytometry (see related content) shows a major population of B-cells positive for CD19, CD20, FMC7 and partial CD79b and negative for CD5, CD10, CD23, kappa and lambda. Plasma cells expressing CD38 and CD138 are <1%.
Case Discussion
Heavy chain diseases (HCD) are B-cell neoplasms that only produce monoclonal heavy chain without associated light chains. There are three types involving the three main immunoglobulin classes: gamma, alpha, and mu.
Gamma heavy chain disease presents like lymphoplasmacytic lymphoma in the bone marrow but lacks light chain. The slides demonstrate the presence of a neoplastic plasma cell population. Monoclonal IgG is seen by immunohistochemistry. Clinically, immunofixation will demonstrate IgG without light chain in the blood and/or urine.
This slide shows bone marrow biopsy, IgG stain. See related content for peripheral blood, bone marrow aspirate, and H&E and IHC of bone marrow biopsies.
Musani, R. Bone Marrow, Gamma Heavy Chain Disease, IgG stain. Digital Laboratory Medicine Library, Dept of Laboratory Medicine & Pathobiology, University of Toronto. Published
. Accessed December 17, 2025. https://dev.dlml.cflabs.ca/image/bone-marrow-gamma-heavy-chain-disease-igg-stain-lmp36665
