Symptoms & Diagnosis

Symptoms & Diagnosis

Symptoms for JMML are typical of any child with many illnesses, but if these symptoms don’t go away on their own quickly, it’s best to see your doctor. Typical JMML symptoms are:

  • Paler skin than usual
  • Fever
  • Infection
  • Bleeding of the skin, mouth and nose

Children with JMML have a cough and fail to gain weight. Many develop a red skin rash and enlarged lymph nodes. Some have small yellowish skin tumors and brown spots (called cafe-au-lait spots), which are characteristic of neurofibromatosis. Other symptoms that your doctor will look for include enlarged liver or spleen, and abnormal blood cell counts, like high white blood cells (leukocytosis), low red blood cells (anemia) and low platelets (thrombocytopenia), in addition to an increased concentration of myelocytes and monocytes.


Because the symptoms for JMML are so similar to several other illnesses, your doctor doctor will perform a physical exam as well as a complete blood cell count, as well as a bone marrow test to make a diagnosis. To test the bone marrow, a marrow aspiration will be performed to remove some of the liquid there, followed by a bone marrow biopsy, which means a small amount of bone with marrow will be removed.

A hematopathologist will make the diagnosis of JMML with the following indications:

  • A persistently high level of monocytes in the blood
  • Less than 20 percent of blast cells in the marrow and blood
  • No indication of chromosomes or markers associated with other types of leukemia. JMML patients may have certain abnormalities with their chromosomes however, from gene mutations to chromosome damage.