http://www.ajcr.us/files/ajcr0000184.pdf Abstract: Mastocytosis is a rare disease characterized by abnormal expansion and accumulation of tissue mast
cells (MC) in one or multiple organs. In most adult patients, systemic mastocytosis (SM) is diagnosed. Based on histopathological
findings and organ damage, SM is divided into indolent SM (ISM), smoldering SM (SSM), SM with an
associated hematologic non-MC-lineage disease (SM-AHNMD), aggressive SM (ASM), and MC leukemia (MCL). The
clinical course and prognosis vary greatly among these groups of patients. In all variants of SM and most patients,
neoplastic cells display the KIT mutation D816V. This suggests that additional KIT-independent molecular defects
cause progression. Indeed, additional oncogenic lesions, including RAS- and TET2 mutations, have recently been
identified in advanced SM. In patients with SM-AHNMD, such additional lesions are often detectable in the ‘AHNMDcomponent’
of the disease. Clinically relevant symptoms of SM result from i) malignant MC infiltration and the subsequent
organ damage seen in advanced SM and/or ii) the release of pro-inflammatory and vasoactive mediators
from MC, found in all disease-variants. Therapy of SM has to be adjusted to the individual situation in each patient.
In ISM, the aim is to control mediator release and mediator effects. In advanced SM, a major goal is to control MC
expansion by using conventional drugs or novel targeted drugs directed against mutant forms of KIT and/or other
pro-oncogenic kinase-targets. In rapidly progressing ASM, MCL and drug-resistant AHNMD, chemotherapy and subsequent
stem cell transplantation has to be considered.