title: Osteopetrosis mimicking juvenile myelomonocytic leukemia.
abstract: A 5-month-old boy developed splenomegaly, anemia, thrombocytopenia with elevated white cells, monocytosis and immature granulocytes in the peripheral blood. Bone marrow showed dysplasia without blastosis. Increased colony-forming unit-granulocyte-macrophage was found in the peripheral blood, mimicking granulocyte-macrophage colony-stimulating factor hypersensitivity. These findings fulfilled the diagnosis criteria for juvenile myelomonocytic leukemia (JMML), but no mutations in the CBL, NRAS, KRAS, or PTPN11 genes were detected. In addition to these findings severe hypogammaglobulinemia and elevated alkaline phosphatase were present. Bone X-ray showed dense and radiopaque bones with a bone-in-bone appearance characteristic of infantile malignant osteopetrosis (IMO). Genetic mutation in T-cell, immune regulator 1 (TCIRG1) was identified, confirming the diagnosis of IMO. Careful differential diagnosis including osteopetrosis, is therefore recommended in patients with clinical features and hematologic findings consistent with JMML.
authors.affiliation: Pediatric Hemato-oncology, CHR Citadelle, Liège, Belgium.
authors.forename: Claire
authors.initials: C
authors.lastname: Hoyoux
authors.forename: Marie Françoise
authors.initials: MF
authors.lastname: Dresse
authors.forename: Patricia
authors.initials: P
authors.lastname: Forget
authors.forename: Caroline
authors.initials: C
authors.lastname: Piette
authors.forename: Léon
authors.initials: L
authors.lastname: Rausin
authors.forename: Anna
authors.initials: A
authors.lastname: Villa
authors.forename: Andre
authors.initials: A
authors.lastname: Gothot
authors.forename: Benoit
authors.initials: B
authors.lastname: Florkin
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D054429:Leukemia, Myelomonocytic, Juvenile / Q000175:diagnosis*; D008297:Male; D010022:Osteopetrosis / Q000175:diagnosis*
keywords: juvenile myelomonocytic leukemia; osteopetrosis