Somatic mosaic mutations of IDH1 and NPM1 associated with cup-like acute myeloid leukemia in a patient with Maffucci syndrome.

Maffucci syndrome is a nonhereditary congenital disorder characterized by multiple enchondromas and with soft-tissue hemangiomas. Somatic mutations of the isocitrate dehydrogenase (IDH) gene have been detected in enchondroma and hemangioma tissue from patients with Maffucci syndrome. The rate of malignant transformation in Maffucci syndrome is high, with enchondromas transforming into chondrosarcomas and the development of secondary neoplasms, including pancreatic and hepatic adenocarcinoma, mesenchymal ovarian tumors, and brain tumors such as glioma. However, hematopoietic malignancies arising in Maffucci syndrome are rare. We report a 7-year-old girl with Maffucci syndrome in whom acute myeloid leukemia (AML) with cup-like nuclear invagination developed. Both leukemic cells and hemangioma had the same gene mutations: an insertion frameshift c.863_864insTCTG (p.W288 fs) in the nucleophosmin (NPM1) gene and a missense mutation c.392_395GTCG > CTCT (p.G131_R132 > AL) in the IDH1 gene. However, buccal mucosa cells and peripheral blood mononuclear cells harvested after two cycles of chemotherapy showed wild-type genotypes. These results suggest that the multiple somatic mutations of the IDH1 and NPM1 genes in hemangioblasts are related to the development of cup-like AML associated with Maffucci syndrome. However, further studies are needed to identify additional molecular events in AML but not in hemangioma.