Clinical and Molecular Diagnostic Evaluation of Systemic Mastocytosis in the South-Eastern Hungarian Population Between 2001-2013--A Single Centre Experience.

Systemic mastocytosis (SM) is a rare chronic myeloproliferative neoplasm with only limited epidemiologic data published so far. We aimed to analyze the clinical and molecular diagnostic features, and the prognosis and cumulative incidence of SM cases in a cohort of south-eastern Hungarian patients of 13 year follow up. In the period 2001-2013, 35 consecutive SM cases were diagnosed in our regional centre. Immunophenotype, KIT D816V mutation frequency and clinical characteristics, and the prognosis impact of clinical subtypes were tested and compared with published data. Indolent SM (ISM) was diagnosed in 14 patients, SM with an associated clonal hematologic non-mast cell lineage disease (SM-AHNMD) in 15 patients and aggressive SM (ASM) in 6 patients. The KIT D816V mutation was found in 11/14 (78%) of the ISM cases, in 12/15 (80%) of the SM-AHNMD cases and in 5/6 (83%) of the ASM cases. The life expectancy of ISM patients was better, whereas the SM-AHNMD and ASM groups exhibited a reduced median survival. The cumulative incidence for 13 year of the SM was 0.27/10,000. We detected lower 13 year cumulative SM incidence than of published epidemiologic data due to in our analyses involved only those patients who had bone marrow biopsy and histopathologically confirmed SM. This clinical overview clearly showed that the clinical characteristics differ between ISM (UP, anaphylaxis and osteoporosis) and SM-AHNMD/ASM (cytopenia, eosinophilia and splenomegaly).