■ Histoplasmosis—Histoplasma capsulatum (fungus)
■ Rhinoscleroma—Klebsiella rhinoscleromatis (gram-negative bacillus)
■ Granuloma inguinale-Calymmatobacterium granulomatis— gram-negative bacillus (Donovan body).
1. Hepburn MC. Cutaneous leishmaniasis. Clin Exp Dermatol 2000; 25:363-370.
2. Grevlink SA, Lerner EA. Leishmaniasis. J M Acad Dermatol 1996; 34:257-272.
URTICARIA PIGMENTOSA, NODULAR
Diffuse dermatitis with prominent mast cells.
■ Generalized eruption
■ Orange-brown macules papules and nodules on trunk less often extremities (Fig. 8A)
■ Often pruritic
■ Lesions develop wheal and flare following trauma (positive Darier's sign)
■ Diffuse mast cell infiltrates throughout much of the dermis (Fig. 8B)
■ Monomorphous mononuclear cells with round to oval centrally placed nuclei and granular amphophilic cytoplasm ("fried egg") (Fig. 8C)
■ Granules are metachromatic (red) with Giemsa stain (Fig. 8D)
■ Tryptase and CD 117 positive
■ Aberrations in C-kit pathway have been implicated References:
1. Yang F et al. Paraffin section immunophenotype of cutaneous and extracutaneous mast cell disease. comparison to other hematopoietic neoplasms. Am J Surg Pathol 2000; 24:703 -709.
2. Buttner C et al. Identification of activating C-kit mutations in adult but not in childhood onset indolent mastocytosis. J Invest Dermatol 1998; 111:1227-1231.
Was this article helpful?