An intriguing coexistence of cutaneous and systemic mastocytosis with atypical chronic myeloid leukemia: An associated hematologic neoplasm (SM-AHN)

Systemic mastocytosis (SM) characterized by focal or diffuse infiltrates of neoplastic mast cells can range from indolent cutaneous disease to aggressive systemic disease. Skin involvement is usual in indolent systemic mastocytosis, less frequent in aggressive SM, and rare in mast cell leukemia. Here, we present a rare coexistence of cutaneous mastocytosis and SM with an associated hematologic neoplasm SM-associated hematologic neoplasm [AHN] (atypical chronic myeloid leukemia [CML]-BCR/ABL negative), the first case being reported in the literature so far to the best of our knowledge. An elderly male with leukocytosis, myeloid hyperplasia, and mast cell infiltrates in the marrow was diagnosed with atypical CML and cutaneous mastocytosis. Approximately 40% of cases of SM are associated with a hematologic neoplasm (SM-AHN) encompassing all defined myeloid neoplasms, such as myelodysplastic syndrome, myeloproliferative neoplasm, acute myeloid leukemia, CML, chronic myelomonocytic leukemia, or plasma cell myeloma. The prognosis of SM-AHN is dependent on the associated hematologic neoplasm (AHN)