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mastocytosis

Abnormal accumulation of mast cells within the skin & at various systemic sites. Classification: 1) generalized cutaneous mastocytosis a) urticaria pigmentosa b) telangiectasia macularis eruptiva perstans (TMEP) c) diffuse cutaneous mastocytosis (DCM) 2) mastocytoma: frequently solitary 3) systemic mastocytosis 4) mast cell leukemia Pathology: 1) epidermis is normal 2) accumulation of normal-looking masts cells in the dermis 3) mast cell infiltrates may be sparse & spindle-shaped orvdense aggregates of cuboidal cells with perivascular or nodular distribution 4) metachromatically stained granules within mast cells (Giemsa or toluidine blue) 5) pigmentation secondary to increase melanin in the basal layer of the epidermis 6) mast cells granules contain several pharmacologically active substances a) histamine: may cause urticaria & GI symptoms b) prostaglandin D2: may cause flushing, cardiovascular symptoms, GI symptoms c) heparin: may cause excessive bleeding at sites of trauma d) neutral proteases & acid hydrolases: may cause patchy hepatic fibrosis & bone lesion 7) bone marrow, liver, spleen, lymph nodes & GI tract may be involved Clinical manifestations: 1) red-brown maculopapular skin lesions - some of which darken & swell when rubbed (Darier's sign) - stroking lesions causes it to itch - when generalized = urticaria pigmentosa 2) various pharmaceutical agents may exacerbate symptoms - alcohol, dextran, polymyxin B, morphine, codeine 3) flushing may be accompanied by: headache, wheezing/dyspnea, diarrhea, syncope 4) bath pruritus (itching after hot bath) 5) cardiovascular: tachycardia, hypertension, syncope 6) GI: nausea/vomiting, diarrhea, malabsorption, portal hypertension 7) neuropsychiatric: malaise, irritability 8) respiratory system: rhinorrhea, wheezing 9) headache 10) anaphylaxis in response to antibiotics (esp penicillin) Laboratory: 1) complete blood count: (systemic mastocytosis) a) anemia b) leukocytosis c) eosinophilia 2) 24 hour urine histamine (36 +/- 15 ug, 2-3 x normal) 3) serum tryptase > 20 ng/mL (< 11.4 ng/mL is normal) 4) bone marrow biopsy with stain for mast cells - Giemsa, toluidine blue, chloral acetate esterase, immunochemical stains for tryptase 5) skin biopsy Radiology: 1) bone scan a) lytic bone lesions b) osteoporosis or osteosclerosis 2) small bowel follow-through Differential diagnosis: - Flushing: carcinoid syndrome - no urticaria - hereditary angioedema - recurrent angioedema of the upper respiratory tract (laryngeal edema) - recurrent angioedema of the gastrointestinal tract (abdomimal pain) - no pruritus or hives - low C1 esterase inhibitor - porphyria - no urticaria, no anaphylaxis Management: 1) avoidance of drugs that cause mast cell degranulation - alcohol, dextran, polymixin B, morphine, codeine, scopalamine, D-tubocurarine, NSAIDs, antihistamines (H1 & H2 antagonists) (ref 1) 2) antihistamines are initial treatment (ref 2) 3) cromolyn 200 mg PO QID may ameliorate flushing, pruritus, urticaria, GI symptoms, neuropsychiatric symptoms 4) corticosteroids for severe cases 5) PUVA treatment: effective, but recurrence common 6) interferon is investigational

Related

Darier's sign mast cell

Specific

diffuse cutaneous (pseudoxanthomatous) mastocytosis (DCM) mast cell leukemia mastocytoma systemic mastocytosis telangiectasia macularis eruptiva perstans (TMEP) urticaria pigmentosa (UP)

General

skin disease (dermatologic disorder, dermatopathy, dermatosis) mast cell disease syndrome

References

  1. Color Atlas & Synopsis of Clinical Dermatology, Common & Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY, 1997, pg 718, 562-65
  2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 32, 178, 298
  3. Murali MR et al. Case records of the Massachusetts General Hospital. Case 9-2011. A 37-year-old man with flushing and hypotension. N Engl J Med 2011 Mar 25; 364:1155. PMID: 21428772
  4. Arock M and Valent P. Pathogenesis, classification and treatment of mastocytosis: state of the art in 2010 and future perspectives. Expert Rev Hematol 2010 Nov 19; 3:497. PMID: 21083038
  5. ARUP Consult: Mast Cell Disorders The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/mast-cell-disorders - Mast Cell Disorders Testing Algorithm https://arupconsult.com/algorithm/mast-cell-disorders-testing-algorithm
  6. NEJM Knowledge+