All patients with mastocytosis are at increased risk for anaphylaxis, a life-threatening event. The prognosis of mastocytosis depends on the specific classification of disease and any comorbid conditions.1-3
In children, some forms of cutaneous mastocytosis (CM) will spontaneously resolve, some will go on to be diagnosed as indolent systemic mastocytosis (ISM), with a smaller percentage identified as well-differentiated systemic mastocytosis (WDSM).4
In most adults with skin lesions typical for mastocytosis [in particular, maculopapular cutaneous mastocytosis (MPCM)/urticaria pigmentosa (UP)], systemic disease will ultimately be found, leading to a diagnosis of systemic mastocytosis (SM), usually in an indolent form (ISM).5, 6 ISM patients have preserved organ function and their survival is typically comparable to that of the general population.1 However, a 3% rate of progression to advanced disease has been noted in some studies, with the serum level of β2-microglobulin and the presence of the KIT D816V mutation in multiple cell lineages helping to predict possible disease progression.2, 7
Patients with smoldering SM (SSM) may have an increased risk of developing disease transformation to advanced forms of SM.
Survival of patients with advanced SM is significantly shorter than that of the general population and is affected by disease subtype.1 Patients with aggressive SM (ASM) suffer debilitating symptoms and have signs of organ dysfunction (C findings). In patients who have SM with an associated hematologic neoplasm (SM-AHN), previously referred to as “SM with associated clonal hematologic non mast cell lineage disease” (SM-AHNMD),8 prognosis can differ depending on the particular myeloproliferative neoplasm.9
Mast Cell Activation Syndrome (MCAS)
Like all patients with mast cell disorders, mast cell activation syndrome (MCAS) patients are at increased risk for anaphylaxis, which, as noted above, is a life-threatening event. Prognosis will likely depend on the type of MCAS and any comorbid conditions.3 As monoclonal MCAS (MMAS) is a more recently described entity, no long-term prognostic data is available; however, the possibility exists that some of these patients may be diagnosed with a form of mastocytosis in follow-up examinations.3 The long-term prognosis for patients with idiopathic MCAS is similarly unknown, as in this form, the cause of the mast cell activation is not known. For secondary MCAS, the prognosis likely depends on or may be influenced by the primary condition causing the MCAS.
- Lim KH, Tefferi A, Lasho TL, Finke C, Patnaik M, Butterfield JH, et al. Systemic mastocytosis in 342 consecutive adults: survival studies and prognostic factors. Blood. 2009 Jun 4;113(23):5727-36. http://www.ncbi.nlm.nih.gov/pubmed/19363219
- Pardanani A. Systemic mastocytosis in adults: 2015 update on diagnosis, risk stratification, and management. Am J Hematol. 2015 Mar;90(3):250-62. http://www.ncbi.nlm.nih.gov/pubmed/25688753
- Valent P. Mast cell activation syndromes: definition and classification. Allergy. 2013 Apr;68(4):417-24. http://www.ncbi.nlm.nih.gov/pubmed/23409940
- Torrelo A, Alvarez-Twose I, Escribano L. Childhood mastocytosis. Curr Opin Pediatr. 2012 Aug;24(4):480-6. http://www.ncbi.nlm.nih.gov/pubmed/22790101
- Berezowska S, Flaig MJ, Rueff F, Walz C, Haferlach T, Krokowski M, et al. Adult-onset mastocytosis in the skin is highly suggestive of systemic mastocytosis. Mod Pathol. 2014 Jan;27(1):19-29. http://www.ncbi.nlm.nih.gov/pubmed/23807778
- Hartmann K, Escribano L, Grattan C, Brockow K, Carter MC, Alvarez-Twose I, et al. Cutaneous manifestations in patients with mastocytosis: Consensus report of the European Competence Network on Mastocytosis; the American Academy of Allergy, Asthma & Immunology; and the European Academy of Allergology and Clinical Immunology. J Allergy Clin Immunol. 2016 Jan;137(1):35-45. http://www.ncbi.nlm.nih.gov/pubmed/26476479
- Escribano L, Alvarez-Twose I, Sanchez-Munoz L, Garcia-Montero A, Nunez R, Almeida J, et al. Prognosis in adult indolent systemic mastocytosis: a long-term study of the Spanish Network on Mastocytosis in a series of 145 patients. J Allergy Clin Immunol. 2009 Sep;124(3):514-21. http://www.ncbi.nlm.nih.gov/pubmed/19541349
- Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016 May 19;127(20):2391-405. http://www.ncbi.nlm.nih.gov/pubmed/27069254
- Pardanani A, Lim KH, Lasho TL, Finke C, McClure RF, Li CY, et al. Prognostically relevant breakdown of 123 patients with systemic mastocytosis associated with other myeloid malignancies. Blood. 2009 Oct 29;114(18):3769-72. http://www.ncbi.nlm.nih.gov/pubmed/19713463