Memorial Sloan Kettering doctors are experienced in caring for people with other plasma cell diseases related to multiple myeloma. Systemic amyloidoses are a group of rare and sometimes serious disorders. Less severe conditions include monoclonal gammopathy of undetermined significance (MGUS) and solitary plasmacytoma. MGUS can lead to myeloma.

Learn more about these multiple myeloma–related blood diseases.

• Systemic Amyloidoses
  In this group of related diseases, a substance called amyloid builds up in tissues throughout the body. It interferes with how organs work and eventually causes them to fail. Learn more about symptoms and treatment options.
• Solitary or Extramedullary Plasmacytoma
  In solitary plasmacytoma, the tumor is restricted to a single area of the body. A extramedullary plasmacytoma tumor develops in the lungs, throat, or other organ. Read about how these tumors are treated at Memorial Sloan Kettering.
• Monoclonal Gammopathy of Undetermined Significance (MGUS)
  Monoclonal gammopathy of undetermined significance can become myeloma. Most people with the disease remain well for years without treatment.