title: Juvenile myelomonocytic leukemia in a 16-year-old with Noonan syndrome: case report.
abstract: A 16-year-old man with splenomegaly presented with ascites and bilateral leg eschars. Although he had intermittently elevated absolute monocyte counts, a diagnosis of juvenile myelomonocytic leukemia (JMML) was discounted because of his age and lack of persistent leukocytosis. Detailed examination demonstrated features consistent with Noonan syndrome (NS), including typical facies, growth retardation, a cardiac defect, and a history of a coagulopathy. He underwent a splenectomy where the surgeons encountered a rind of tissue composed of monocytes encasing the abdominal organs. After splenectomy, his leukocytes rose to over 100×10(9)/L with a monocytosis, suggesting JMML. On the basis of the clinical suspicion of NS, mutation analysis revealed a KRAS mutation, which is known to be common to both NS and JMML. Clinicians should have high index of suspicion for JMML in patients with Noonan features, regardless of a patient's age.
authors.affiliation: Department of Pediatrics, Children's National Medical Center, Washington, DC, USA.
authors.forename: Michael Vincent
authors.initials: MV
authors.lastname: Ortiz
authors.forename: Suzanne
authors.initials: S
authors.lastname: Skoda-Smith
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Rauen
authors.forename: Robert W
authors.initials: RW
authors.lastname: Allan
authors.forename: William Birdsall
authors.initials: WB
authors.lastname: Slayton
mesh_terms: D000293:Adolescent; D006801:Humans; D054429:Leukemia, Myelomonocytic, Juvenile / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D009154:Mutation; D009634:Noonan Syndrome / Q000150:complications*; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins