Place of cytology in the diagnosis of systemic mastocytosis: A case report

Mastocytosis is a heterogeneous group of rare diseases related to the clonal, neoplastic proliferation of morphologically and immunophenotypically abnormal mast cells, that accumulate in one or more organ systems. Their pathophysiology is dominated by activating mutations in C-Kit (Stem Cell Factor receptor). Several pathological forms have been described ranging from isolated cutaneous mastocytosis affecting mainly children, to aggressive systemic mastocytosis described mainly in adults with bone marrow involvement. According to the WHO 2016 classification of hematological malignancies, systemic mastocytosis appear as a new entity of "myeloid neoplasms and acute leukemias" that combines cytology (abnormal mast cells) with other genetic and molecular criteria. We describe through this observation the practical side of hematological cytology in the diagnostic orientation of this serious, rare and underestimated pathology.