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Multiple myeloma
Other Resources UpToDate PubMed

Multiple myeloma

Contributors: Nicole Golbari MD, Susan Burgin MD, Paritosh Prasad MD
Other Resources UpToDate PubMed


Multiple myeloma (MM) is characterized by the neoplastic proliferation of plasma cells resulting in a monoclonal gammopathy. Plasma cells proliferate in the bone marrow and may result in osteolytic lesions, in some cases complicated by pathologic fracture.

MM is a disorder of adults (median age of diagnosis is 66 years) characterized by serum and/or urinary monoclonal proteins, hypercalcemia (38% of cases), anemia (about 80% of cases), painful lytic bone lesions (58%-70% of cases, often with fractures), decreased renal function with elevated creatinine (about 25%-48% of cases), and sometimes symptoms related to compression of the spinal cord (about 5% of cases). Rarely, corneal crystalline deposits may occur.

Infections, especially with encapsulated pyogenic organisms such as Haemophilus, Staphylococcus, and Streptococcus, are increased in patients with MM. Plasma cells are increased (10% or greater) in the bone marrow.

MM accounts for about 17% of hematologic malignancies in the United States and 1%-2% of all cancers. The disorder is twice as common in Africans and African Americans and is more common in males. Rare cases of myeloma have occurred after bone marrow transplant for leukemia.

Evaluation using serum and urine electrophoresis (SPEP and UPEP) reveals monoclonal protein in 97% of cases.

MM rarely presents with cutaneous involvement, and skin manifestations are typically apparent late in disease course and associated with reduced overall survival. Extramedullary plasmacytomas, although rare, are the most specific cutaneous finding. However, urticaria, amyloidosis, leukocytoclastic vasculitis, autoimmune bullous lesion formation, and pyoderma gangrenosum have been reported as the initial presentation of MM. These are sometimes related to the location of needle sticks and bone marrow aspirations.

Other skin findings in MM include:


C90.00 – Multiple myeloma not having achieved remission

109989006 – Multiple myeloma

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Differential Diagnosis & Pitfalls

Differential diagnosis of skin findings:

Extramedullary plasmacytoma –
Follicular spicules
Vasculitis and cryoglobulinemia – Consider other forms of vasculitis, including drug reactions and hepatitis B and C.

Amyloidosis – Consider other causes of purpura and infiltrative disorders, such as nodular amyloidosis (ie, localized cutaneous amyloidosis), lichen amyloidosis, scleredema, etc.

Schnitzler syndrome – Other causes of fever, joint pain, and urticarial rash including urticarial vasculitis, chronic idiopathic urticaria, adult-onset Still disease, and cryopyrin-associated periodic syndrome.

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Last Reviewed:12/17/2018
Last Updated:07/11/2023
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