mastocytosis
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Introduction
Abnormal accumulation of mast cells within the skin & at various systemic sites.
Classification
- generalized cutaneous mastocytosis
- mastocytoma: frequently solitary
- systemic mastocytosis
- mast cell leukemia
Pathology
- epidermis is normal
- accumulation of normal-looking masts cells in the dermis
- mast cell infiltrates may be sparse & spindle-shaped orvdense aggregates of cuboidal cells with perivascular or nodular distribution
- metachromatically stained granules within mast cells (Giemsa or toluidine blue)
- pigmentation secondary to increase melanin in the basal layer of the epidermis
- mast cells granules contain several pharmacologically active substances
- histamine: may cause urticaria & GI symptoms
- prostaglandin D2: may cause flushing, cardiovascular symptoms, GI symptoms
- heparin: may cause excessive bleeding at sites of trauma
- neutral proteases & acid hydrolases: may cause patchy hepatic fibrosis & bone lesion
- bone marrow, liver, spleen, lymph nodes & GI tract may be involved
Clinical manifestations
- 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
- various pharmaceutical agents may exacerbate symptoms
- flushing may be accompanied by: headache, wheezing/dyspnea, diarrhea, syncope
- bath pruritus (itching after hot bath)
- cardiovascular: tachycardia, hypertension, syncope
- GI: nausea/vomiting, diarrhea, malabsorption, portal hypertension
- neuropsychiatric: malaise, irritability
- respiratory system: rhinorrhea, wheezing
- headache
- anaphylaxis in response to antibiotics (esp penicillin)
Laboratory
- complete blood count: (systemic mastocytosis)
- 24 hour urine histamine (36 +/- 15 ug, 2-3 x normal)
- serum tryptase > 20 ng/mL (< 11.4 ng/mL is normal)
- bone marrow biopsy with stain for mast cells
- skin biopsy
Radiology
- bone scan
- 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
- avoidance of drugs that cause mast cell degranulation
- alcohol, dextran, polymixin B, morphine, codeine, scopalamine, D-tubocurarine, NSAIDs, antihistamines (H1 & H2 antagonists) (ref 1)
- antihistamines are initial treatment (ref 2)
- cromolyn 200 mg PO QID may ameliorate flushing, pruritus, urticaria, GI symptoms, neuropsychiatric symptoms
- corticosteroids for severe cases
- PUVA treatment: effective, but recurrence common
- interferon is investigational
More general terms
More specific terms
- diffuse cutaneous (pseudoxanthomatous) mastocytosis (DCM)
- mast cell leukemia
- mastocytoma
- systemic mastocytosis
- telangiectasia macularis eruptiva perstans (TMEP)
- urticaria pigmentosa (UP)
Additional terms
References
- ↑ Color Atlas & Synopsis of Clinical Dermatology, Common & Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY, 1997, pg 718, 562-65
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 32, 178, 298
- ↑ 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: https://www.ncbi.nlm.nih.gov/pubmed/21428772
- ↑ 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: https://www.ncbi.nlm.nih.gov/pubmed/21083038
- ↑ 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 - ↑ NEJM Knowledge+