Atypical IgM multiple myeloma with deletion of c-MAF

Int J Lab Hematol. 2015 Oct;37(5):686-9. doi: 10.1111/ijlh.12385. Epub 2015 May 20.


IgM multiple myeloma (MM) is a rare subtype of myeloma that shares clinical and pathological features with Waldenström's macroglobulinaemia. These are two separate entities that differ both in therapy and prognosis. We report a 57-year-old male, who presented with anaemia, hypercalcaemia, acute renal failure and several vertebral fractures that clinically suggested a multiple myeloma. Further investigations revealed a serum monoclonal component of IgM lambda type and a bone marrow infiltrated by small, lymphoplasmocytic cells. IgM MM was finally diagnosed by means of both inmunophenotypic and immunohistochemistry techniques, stressing the importance of inmunophenotypic evaluation when clinical and morphological features are discordant. Fluorescence in situ hybridization (FISH) studies disclosed a particular combination of deletion 13q14, t(11;14) and monoallelic deletion C-MAF without t(14;16). The clinical evolution after a Bortezomib-containing polychemotherapy and autologous stem cell transplantation (ASCT) conditioned with busulphan and melphalan is also presented. This very uncommon case highlights the impact of immunophenotyping on the differential diagnosis between IgM MM and WM, to choose the best treatment and establish an appropriate outcome.

Keywords: C-MAF; Multiple myeloma; Waldenström's macroglobulinemia.

Publication types

  • Case Reports

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Biopsy
  • Bone Marrow / pathology
  • Diagnosis, Differential
  • Gene Deletion*
  • Humans
  • Immunoglobulin M / blood*
  • Immunophenotyping
  • Male
  • Middle Aged
  • Multiple Myeloma / blood*
  • Multiple Myeloma / diagnosis
  • Multiple Myeloma / drug therapy
  • Multiple Myeloma / genetics*
  • Proto-Oncogene Proteins c-maf / genetics*
  • Treatment Outcome
  • Waldenstrom Macroglobulinemia


  • Immunoglobulin M
  • Proto-Oncogene Proteins c-maf