title: Two Cases of Heavy Chain MGUS.
abstract: Heavy chain diseases are rare variants of B-cell lymphomas that produce one of three classes of immunoglobulin heavy chains, without corresponding light chains. We describe two patients with asymptomatic heavy chain monoclonal gammopathy. The first patient is a 51-year-old woman with alpha paraprotein on serum immunofixation. The second case is a 46-year-old woman with gamma paraprotein on urine immunofixation. Neither patient had corresponding monoclonal light chains. Workup for multiple myeloma and lymphoma was negative in both patients. These two cases illustrate that heavy chain monoclonal gammopathy can exist in the absence of clinically apparent malignancy. Only a few reports of "heavy chain MGUS" have been described before. In the absence of specialized guidelines, we suggest a similar follow-up as for MGUS, while taking into account the higher probability of progression to lymphoma than to myeloma.
authors.affiliation: Nephrology, Dialysis and Renal Transplantation, University Hospitals Leuven, 3000 Leuven, Belgium.
authors.forename: Jan
authors.identifier: 0000-0003-4490-5170
authors.initials: J
authors.lastname: Van Keer
authors.affiliation: Nephrology, Dialysis and Renal Transplantation, University Hospitals Leuven, 3000 Leuven, Belgium; Laboratory of Nephrology, Department of Microbiology and Immunology, KU Leuven, 3000 Leuven, Belgium.
authors.forename: Björn
authors.initials: B
authors.lastname: Meijers
authors.affiliation: Hematology, University Hospitals Leuven, 3000 Leuven, Belgium; Laboratory for Stem Cell Biology and Embryology, Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium.
authors.forename: Michel
authors.initials: M
authors.lastname: Delforge
authors.affiliation: Hematology, University Hospitals Leuven, 3000 Leuven, Belgium; Laboratory for Experimental Hematology, Department of Oncology, KU Leuven, 3000 Leuven, Belgium.
authors.forename: Gregor
authors.initials: G
authors.lastname: Verhoef
authors.affiliation: Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; Laboratory for Molecular Neurobiomarker Research, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Poesen