Complex karyotype and absence of mutation in the c-kit receptor in aggressive mastocytosis presenting with pelvic osteolysis, eosinophilia and brain damage

Aggressive mastocytosis is a form of systemic mast cell disease (SMCD) char acterized by organ infiltration, bone lesions, eosinophilia and lymphadenop athies. Here we report a patient with unusual clinical features, namely ost eolysis without other bone lesions commonly found in SMCD, major eosinophil ia and cerebral infarction. The mast cells exhibited a classical immunophen otype (CD2+, CD9+, CD13+, CD25+, CD35+, CD45c+ and CD117+). Cytogenetic inv estigation showed novel complex aberrations, and clonal evolution was corre lated with clinical progression. The screening for recurrent point mutation s affecting the c-kit gene was negative. Mainly, the ASP816VAL substitution was not detected in our patient. Treatment with steroids and interferon wa s only temporarily effective.