MAST CELL DISEASE
This includes a wide spectrum of clinical entities, with urticaria pigmentosa with or without systemic lesions, and may rarely be associated with malignant mast cell leukemia. Symmetrical hyperpigmented macules or papules may develop from infancy, most commonly on the trunk; they urticate on mild trauma. Vesiculation, erythema, and telangiectasia may develop. Pruritus is common and may be accompanied by flushing, tachycardia, and malaise. Familial instances with autosomal dominant trait inheritance have been described (Shaw 1968). A somatic point mutation in KIT may be detected in peripheral blood mononuclear cells in patients with mastocytosis with an associated hematological disorder (Nagata et al. 1995; Fritsch-Polanz et al. 2001; Ferger et al. 2002; Chang et al. 2001). TET2 mutations have been found in the bone marrow of affected cases (Tefferi et al. 2009).