KIT and Splenomegaly: In this regard, our proposal for centres unable to determine the pattern of KIT mutation in the different BM compartments of hematopoietic cells, would be to perform an initial follow-up of patients with ISM managed with conservative measures, by monitoring sBT every 6 months during the first 4 years after diagnosis, in order to estimate the sBT slope; in parallel, special attention should also be paid to the development of hepatomegaly plus splenomegaly and diffuse bone sclerosis (Figure 2).