CLINICAL HISTORY:

Signs and symptoms:  Upon review of history, patient admitted to recurrent episodes of headaches, fainting spells, flushing, pruritus, palpitations, wheezing, abdominal pain, and vomiting within the last year. Her skin lesions periodically become raised, erythematous, and pruritic, which are exacerbated with “asthma attacks.” Exercise and naprosyn worsen her symptoms and induce acute attacks. Neurocardiogenic syncope was also noted on medical history.

Previous Treatment:  Laser, intralesional and topical corticsteroids.

Other information:  Medications upon presentation include Advair, Combivent, Synthroid, Singulair, and Yasmine.

PHYSICAL EXAM:

Examination reveals numerous reddish-brown, well-demarcated macules and papules less than 1 cm in diameter. These lesions are symmetrically distributed, most numerous on the trunk, buttocks and proximal extremities. The face is spared.

Thigh Macules

Macules on Chest

LABORATORY TESTS:

CBC, CMP, rheumatoid factor, ANA, SPEP, and serum tryptase were all within normal limits. In addition, karyotype and bone marrow biopsy with flow cytometry were also within normal limits. Peripheral blood smear showed the pelger-huet anomaly.

DERMATOHISTOPATHOLOGY:

Increased superficial dermal perivascular cells with granular cytoplasm. The cells stained metachromatically with Giemsa. These findings are consistent with mastocytosis.

H&E

Geimsa

DIFFERENTIAL DIAGNOSIS:

1.   Systemic Mastocytosis
2.   Carcinoid syndrome
3.   VIPoma
4.   Zollinger-Ellison syndrome
5.   Pheochromocytoma

SCROLL DOWN FOR ANSWER AND DISCUSSION.

CORRECT DIAGNOSIS:

Urticaria Pigmentosa

DISCUSSION:

Mastocytosis (MC) is a heterogeneous group of disorders characterized by abnormal proliferation and accumulation of mast cells in the skin, bone marrow, gastrointestinal tract, liver, spleen, and lymph nodes. The spectrum of mast cell disease has been classified based on type and extent of involvement as well as age of onset.

Cutaneous forms include solitary mastocytoma, urticaria pigmentosa, diffuse cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans. Urticaria pigmentosa is the most common form of cutaneous MC. Urticaria pigmentosa (UP) usually presents in childhood and can persist into adulthood, however, most spontaneously improve.

Patients with UP may also experience various systemic symptoms such as pruritus, flushing, dizziness, palpitations, syncope, nausea, diarrhea, abdominal pain, headache, musculoskeletal pain, and neuropsychiatric disturbances.

Serum tryptase levels and 24-hour urine histamine metabolites are the most useful lab test for MC. High levels of soluble CD117 and CD25 receptors are strongly associated with severity of bone marrow involvement. MC can be associated with mutations in codon 816 c-kit, a proto-oncogene that encodes for KIT, the receptor for stem cell factor. This mutation may contribute to an increased rate of mast cell proliferation.

TREATMENT:

Therapy is aimed at minimizing signs and symptoms related to histamine release. This includes, avoiding triggers, H1/H2 antagonists, oral cromolyn sodium, PUVA, and topical/intralesional steroids.

REFERENCES:

1. Bolognia JL, Jorizzo JL, Rapini RP, et. al. (2003) Dermatology. Spain: Mosby
2. Schwartz LB - Immunol Allergy Clin North Am - 01-AUG-2006; 26(3): 451-63
3. Shaffer HC - J Am Acad Dermatol - 01-MAY-2006; 54(5 Suppl): S210-3
4. Valent P - Immunol Allergy Clin North Am - 01-AUG-2006; 26(3): 515-34
5. Bishop AB - J Am Acad Dermatol - September 2006; 55(3); 553-556

Additional Comment:

As noted in our patient, extensive workup has not revealed any evidence of systemic disease. Despite her relatively low mast cell burden, normal tryptase level, and negative bone marrow biopsy, she continues to have symptoms even with aggressive medical therapy. Our case supports the literature in that there is little correlation between clinical extent of disease and severity of symptoms.
This patient will be closely monitored in conjunction with an allergist, as there is a risk of progression into more aggressive disease. Repeat bone marrow biopsy should be considered if tryptase level trends upward.

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