A case report of mast cell leukemia in a child and literature review

Mast cell leukemia (MCL) is a very rare form of aggressive systemic mastocytosis accounting for < 1% of all mastocytosis. Mastocytosis is a broad term used for a group of clonal disorders characterized by accumulation of mast cells in the skin with or without extracutaneous involvement. The clinical spectrum of the disease varies from only cutaneous lesions to highly aggressive systemic involvement such as MCL. Mastocytosis can present from birth to adulthood. In children, mastocytosis is usually benign, and there is a good chance of spontaneous regression at puberty, unlike adult-onset disease, which is generally systemic and more severe. Individuals with systemic mastocytosis may be at risk of developing hematologic malignancies. MCL diagnosis requires the presence of SM criteria with additional features including leukemic infiltration of bone marrow and/or blood by at least 20% high-grade MC as well as the infiltration of extracutaneous organs by neoplastic MC. Genetic aberrations, mainly the KIT D816V mutation, play a crucial role in the pathogenesis of mastocytosis and are detected in most patients. To date, there is no approved standard therapy. For MCL, few options are available for treatment and because of the rarity of the disease very few clinical trials address the question. Even if SM occurs occasionally, all children with mastocytosis require planned follow-up over time. We present an overview of literature on MCL and a rare case of MCL diagnosed in a 4-year-old girl who had had cutaneous mastocytosis since early childhood. A bone marrow examination revealed MCL. She ultimately died despite chemotherapy. The patient's parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.