Isolated Bone Marrow Mastocytosis may be Associated with Reduced Overall Survival

Mastocytosis is characterized by accumulation/proliferation of abnormal Mast Cells (MCs) in tissues [1]. Depending on organ involvement, two main forms of mastocytosis are identified Isolated Cutaneous Mastocytosis (ICM), when the skin is the only tissue affected [2,3] and Systemic Mastocytosis (SM), characterized by MC infiltrates in internal organs, mostly the Bone Marrow (BM). SM can be or not associated with concomitant skin involvement. The most frequent form of SM is indolent SM [4]. Isolated Bone Marrow Mastocytosis (IBMM) constitutes a variant of indolent SM described in the 2008 WHO classification for mastocytosis [5]. There are limited information on the course and prognosis of IBMM in the literature. In the literature, it exist for patients with non-advanced and advanced mastocytosis a score who can be used to predict survival outcomes even if the predictive value of the International Prognostic Scoring system for Mastocytosis (IPSM) needs to be confirmed in forthcoming trials [6]. IBMM represents a diagnostic challenge for clinicians as clinical manifestations such as anaphylaxis; osteoporosis and digestive symptoms are not specific. The main objective of this study was to analyze the overall survival of patients with IBMM in adults with SM. The secondary objectives were to assess the frequency of IBMM in adults with SM, compare the clinical and laboratory characteristics of patients IBBM to those of patients with SM associated cutaneous mastocytosis (SMcm) and evaluate the IPSM prognostic score in our cohort.