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

Over the last decade significant advances have been made by honing in on the diagnostic evaluation and the significance of molecular profiles in patients with systemic mastocytosis (SM), non-advanced and advanced.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 the treatment paradigm.Patients with SM and an associated hematologic neoplasm (SM-AHN) comprise of up to 70% of those in the advanced SM category, posing varying challenges in diagnosis and clinical heterogeneity due to the occupation of the bone marrow niche by two hematologic neoplasms.We are constantly learning about the complex, heterogenous genotypic and phenotypic spectrum of these patients with a view to provide personalised treatment options, aiming to improve outcomes, quality of life and ultimately a cure. This paper focuses on the management of patients with advanced systemic mastocytosis with an associated hematologic neoplasm and is a personal perspective using some illustrative patient cases treated at our centre, Guys and St Thomas's Hospitals, London: UK centre of excellence in Mastocytosis.