Systemic mastocytosis associated with myelodysplastic/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis: Report of three cases.

The association of systemic mastocytosis with another hematologic neoplasia of myeloid or lymphoid origin is recognized as an advanced subvariant of mastocytosis. Here, we report the association of indolent or smoldering systemic mastocytosis with three cases of myelodysplastic/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis, a recently recognized disease characterized by SF3B1 mutations. The hierarchical pattern of KIT, SF3B1, JAK2, and additional mutations was studied in whole and fractionated subpopulations of peripheral blood cells and whole bone marrow. In two cases, we could demonstrate a multilineage D816V KIT mutation, involving all myeloid lineages in one patient and also the lymphoid series in the other. Two patients displaying both SF3B1 and V617F JAK2 mutations had a very poor prognosis. Another patient bearing SF3B1, but not V617F JAK2 mutation, had a favorable response to erythropoietin treatment and long survival.

Whole-Exome Sequencing Reveals Recurrent but Heterogeneous Mutational Profiles in Sporadic WHO Grade 1 Meningiomas.

Human WHO grade 1 meningiomas are generally considered benign tumors; despite this, they account for ≈50% of all recurrent meningiomas. Currently, limited data exist about the mutational profiles of grade 1 meningiomas and patient outcome. We investigated the genetic variants present in 32 WHO grade 1 meningiomas using whole exome sequencing, and correlated gene mutational profiles with tumor cytogenetics and patient outcome. Overall, WHO grade 1 meningiomas harbored numerous and heterogeneous genetic variants, which most frequently affected the NF2 (47%) gene and to a less extent the PNMA6A (22%), TIGD1 (16%), SMO (13%), PTEN (13%), CREG2 (9%), EEF1A1 (6%), POLR2A (6%), ARID1B (3%), and FAIM3 (3%) genes. Notably, non-synonymous genetic variants of SMO and POLR2A were restricted to diploid meningiomas, whereas NF2 mutations were only found among tumors that showed -22/22q─ (with or without a complex karyotype). Based on NF2 mutations and tumor cytogenetics, four genetic profiles were defined with an impact on patient recurrence-free survival (RFS). These included (1) two good-prognosis tumor subgroups-diploid meningiomas (n=9) and isolated -22/22q─ associated with NF2 mutation (n=7)-with RFS rates at 10 y of 100%; and (2) two subgroups of poor-prognosis meningiomas-isolated -22/22q─ without NF2 mutation (n=3) and tumors with complex karyotypes (n=11)-with a RFS rate at 10 y of 48% (p=0.003). Our results point out the existence of recurrent but heterogeneous mutational profiles in WHO grade 1 meningiomas which have an impact on patient outcome.