Mu Heavy Chain Disease Clinical Presentation

Updated: Oct 13, 2017
  • Author: Jessica Katz, MD, PhD, FACP; Chief Editor: Emmanuel C Besa, MD  more...
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The presenting signs and symptoms of mu heavy chain disease (mu-HCD) are generally secondary to the associated lymphoproliferative disorder, such as chronic lymphocytic leukemia (CLL), lymphoproliferative disorder, or myeloma. Patients may show evidence of systemic disease, such as weight loss, fever, night sweats, and recurrent infection. [8]

Initial reported cases of mu-HCD had a clinical picture consistent with CLL; however, with better diagnostic procedures and a high index of suspicion, the defining protein abnormality has been noted in a broader range of clinical settings. Currently, only one third of patients with mu-HCD appear to have CLL. In 150 consecutive patients with CLL, thorough investigation of serum proteins failed to identify a single instance of mu-HCD, which suggests an incidence of less than 1% in this population. [9]

Other clinical presentations vary, one of which may be essential monoclonal gammopathy with no clinical symptoms of B-cell lymphoma (20%). [10] In 10% of cases, an intact IgM protein was simultaneously detected in the serum. Another 10% of cases were associated with clinical multiple myeloma or plasmacytoma. Mu-HCD is also reported to be associated with systemic amyloidosis in rare instances. [8]


Physical Examination

Physical examination findings are variable in patients with mu-HCD, but may include the following:

  • Splenomegaly is almost universal.
  • Hepatomegaly is noted in 75% of cases.
  • Peripheral lymphadenopathy is present in 40% of cases.
  • Bone pain from lytic lesions is present in 40% of cases.
  • Pallor may be noted if significant anemia is present, which is usually observed only in advanced disease.