ISSN 2398-2969      

Myeloma

icanis

Synonym(s): Multiple myeloma, plasma cell myeloma, plasma cell neoplasm


Introduction

  • Accounts for 8% of all hematopoietic tumors.
  • Cause: proliferation of neoplastic plasma cells in bone marrow.
  • Signs: non-specific, hyperviscosity.
  • Diagnosis: laboratory results, bone marrow cytology, radiographic lesions.
  • Treatment: chemotherapy (melphalan and prednisolone).
  • Prognosis: may be controlled with treatment.

Pathogenesis

Etiology

  • Unknown.
  • Possible causes - genetic predisposition, viral infection (but not FeLV or FIV), chronic immune stimulation, exposure to carcinogens.

Pathophysiology

  • Proliferation of neoplastic plasma cells usually → secretion of monoclonal immunoglobulin (paraprotein) → hyperviscosity and other clinical signs.
  • Neoplastic plasma cells proliferate in bone marrow.
  • In most cases these cells secrete an abnormal immunoglobulin (paraprotein) (usually IgA or IgG heavy or light chain fragments) → excretion of immunglobulin leads to renal tubular damage.
  • The paraprotein may be a cryoglobulin.
  • Hyperproteinemia or monoclonal gammopathy affects platelet function and may interfere with clotting mechanisms.
  • Increased serum viscosity (particularly with IgA secreting myelomas) → circulatory impairment with cardiovascular, respiratory, neurological and ocular signs (hyperviscosity syndrome).
  • Some non-secretory myelomas have been reported.
  • Antibody coating of red blood cells → hemolysis (Coomb's positive anemia).
  • Increased percentage of plasma cells in marrow → anemia, leukopenia and thrombocytopenia.
  • Abnormal plasma cells → reduced immune function.
  • Hypercalcemia seen in 20% of cases.
  • Anemia due to reduced marrow synthesis and increased RBC fragility.

Timecourse

  • Insidious onset.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Chaffin K et al (1998) Extramedullary plasmacytoma in the trachea of a dog. JAVMA 212 (10), 1579-1581 PubMed.
  • Hendrix D V H et al (1998) Ophthalmic disease as the presenting complaint in five dogs with multiple myeloma. JAAHA 34 (2), 121-128 PubMed.
  • Villiers E & Dobson J (1998) Multiple myeloma with associated polyneuropathy in a German Shepherd Dog. JSAP 39 (5), 249-251 PubMed.
  • Hammer A S & Couto C G (1994) Complications of multiple myeloma. JAAHA 30 (1), 9-14 VetMedResource.

Other sources of information

  • Vail D M (2007)Plasma cell neoplasms.In:Small Animal Clinical Oncology.4th edn. Eds S J Withrow & E G MacEwen. Philadelphia: W B Saunders & Co. pp 769-782.
  • Vail D M (2000)Hematopoietic tumors. In:Textbook of Veterinary internal Medicine.5th edn. Eds S J Ettinger & E C Feldman. Philadelphia, PA: W B Saunders Co. pp 516-520.

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