How I diagnose and treat systemic mastocytosis with an associated hematologic neoplasm.

Over the last decade significant advances have been made by honing the diagnostic evaluation and the significance of molecular profiles in patients with nonadvanced and advanced systemic mastocytosis (AdvSM). This is reflected in the 2022 iterations of the World Health Organization edition 5 and International Consensus Criteria classifications. The impact of targeted KIT inhibitor therapies on patients treated within global trials has demonstrated significant improvements in the prognosis and overall survival for patients, leading to a change in the treatment paradigm. Patients with SM and an associated hematologic neoplasm (AHN) comprise up to 70% of those in the advanced SM category, posing varying challenges in diagnosis and clinical heterogeneity because of the occupation of the bone marrow niche by 2 hematologic neoplasms. We are constantly learning about the complex, heterogenous genotypic and phenotypic spectrum of these patients with a view to provide personalized treatment options, aiming to improve outcomes, quality of life, and ultimately a cure. This paper focuses on the management of patients with AdvSM with an AHN and is a personal perspective using some illustrative patient cases treated at our center, Guy's and St Thomas' Hospitals, London, UK center of excellence in mastocytosis.