Myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS/MPN-U) is a distinct disease among the myeloid neoplasms, characterized by the simultaneous presence of both dysplastic (abnormal appearing cells) and proliferative features (too many cells or not the right kinds), but is not chronic myelomonocytic leukemia, juvenile myelomonocytic leukemia, or atypical chronic myelogenous leukemia.

In MDS/MPN-U, the body makes too red blood cells, white blood cells, or platelets but some of the cells are not made properly. MDS/MPN-U is thought to be caused by mutations in blood stem cells and these mutations cause the blood stem cells to behave abnormally. Over time, immature cells called “blasts” begin to accumulate in the body in some patients with MDS/MPN-U. Over time, MDS/MPN-U can convert to an acute leukemia or can lead to progressive failure of normal blood cell formation. This can lead to abnormally low numbers of red blood cells, white blood cells and platelets.

Patients with MDS/MPN-U can have severe symptoms, few symptoms or none at all. Most symptoms and medical problems experienced by patients with MDS/MPN-U are caused by the abnormal blood cell counts. Fatigue is fairly common. Other symptoms include, fever, weight loss, shortness of breath, pale skin, easy bruising or bleeding, pain or a feeling of fullness below the ribs.

MDS/MPN-U is an uncommon disease, making up less than 5% of all myeloid disorders, and therefore, the factors that affect someone’s risk and prognosis need to be further researched to be able to better diagnose and treat the disease. There is currently no standard treatment for MDS/MPN-U. Physicians will typically base their treatment decision on the best available MPN or MDS therapies. It is through volunteers who enroll in clinical trials that clinicians can conduct the necessary research that has the potential to lead to standard of care treatments for this rare disease.




Richard T. Silver MD Myeloproliferative Neoplasms Center 525 East 70th St., Starr Pavillion, 3rd Floor New York, NY 10021