General Overview and Incidence
Mastocytosis is no longer under the broad category of myeloproliferative neoplasm (MPN). Mastocytosis is a heterogeneous disease of clonal neoplastic proliferation and expansions of mast cells (MCs) that are CD117 + /CD25 + /CD2 + and CD34 negative or delete CD34, and involve the skin, bone marrow, spleen, gastrointestinal tract, liver, and lymph nodes with indolent to aggressive forms and can be associated with hematologic neoplasms, systemic mastocytosis (SM)-associated hematologic neoplasm (SM-AHN), further designated into myeloid or lymphoid neoplasms. , Myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) include chronic neutrophilic leukemia (CNL), atypical chronic myelogenous leukemia (CML), myelodysplastic/myeloproliferative neoplasms with ringed sideroblasts and thrombocytosis (MDS/MPN-RS-T), chronic myelomonocytic leukemia (CMMOL-0, 1, 2), and juvenile myelomonocytic leukemia (JMML).
SM occurs in 1 in 10,000 or 0.89 per 100,000 people per year. MCs are physiologically activated by binding of stem cell factor to the extracellular domains of the Kit receptor with subsequent MC mediator release and/or infiltration of MCs into tissues. Aberrant KIT activation results in increased production of MCs in the skin and extracutaneous organs. Somatic mutations of the coding KIT gene cause autocrine dysregulation and lead to constitutive KIT activation even in the absence of its ligand stem cell factor.
Systemic (fatigue, general malaise, weight loss, anaphylaxis to bee or wasp venom)
Cardiovascular (hypotension, syncope, light-headedness, tachycardia)
Cutaneous (flushing, pruritus, urticaria, angioedema)
Digestive (abdominal cramps, diarrhea, esophageal reflux, nausea and vomiting)
Musculoskeletal (aches, bone pain, osteopenia and osteoporosis)
Neurologic (anxiety, depression, decreased concentration and memory, insomnia and migraines)
Respiratory (nasal congestion, nasal pruritus, shortness of breath, throat swelling, wheezing)
The updated World Health Organization classification of mastocytosis with additional refined criteria is discussed and referenced. , ,
Laboratory Manifestations/Pathologic Features
SM can involve: