Ually occurs in the tropical belt of Pimecrolimus Elidel Africa, between the Tropics of Cancer and Capricorn, and in Madagascar. It has rarely been reported outside Africa, mainly in migrants or former inhabitants of the continent.1 3 Fewer than 300 cases had been reported up to 2007, only a few of them arising in the context of HIV infection.1,3 The causal agent is H. capsulatum var. duboisii, which differs in some aspects, such as fatty acid profile, cell wall glycan structure, or lack of urease6,7 from the more commonly encountered Histoplasma capsulatum var. capsulatum. The fungus has recently been isolated from soil containing bat excrements in Nigeria6 thus accounting for the association of cases with a history of previous exposure to caves infested with bat droppings or to contaminated soil, like classical histoplasmosis.1 Unlike classical histoplasmosis, which mainly occurs in the lungs, tissues most frequently involved in African histoplasmosis include skin, subcutaneous tissue, and bones, although lymph node, spleen, hepatic, pulmonary or gastrointestinal lesions have also been described in disseminated disease.5,6,8,9 Unusual clinical presentations so far reported include Addison’s disease,10 a gastric ulcer,11 peritonitis caused by perforation of an intestinal lesion,12 a colonic tumor,13 and an orbital cyst.14 Unlike the case hereby reported, cutaneous lesions are usually multiple, appear simultaneously, and incubation can be very long going, sometimes several months or years after exposure.1 Histology shows a mainly granulomatous inflammation, with a prominent component of huge multinucleate giant cells, both of foreign body and Langhans type, containing many oval or lemon shaped, thick walled, 8 15 mm large yeast cells, in contrast to those of H. capsulatum var. capsulatum, which do not exceed 5 mm. Fungal cells divide by narrow budding.
They are easily identified in tissue sections by virtue of time honored histochemical stains, such as PAS or Grocott methenamine silver. Differential diagnosis mainly includes Cryptococcus and Penicillium species: the lack of a mucicarminophilic halo excludes Cryptococcus, whereas Penicillium yeasts divide by intracellular septation, not by narrow budding.15 18 Although specific primary antibodies for immunostaining of H. capsulatum var. capsulatum yeasts in tissue sections are available,19 no such report exists up to now for H. capsulatum var. duboisii. There is a more prominent giant cell component in histologic sections of African, compared with classical histoplasmosisAlthough the reason for this difference has not yet been elucidated, recently identified differences in fatty acid profile or cell wall glycan structure between the two varieties of H. capsulatum7 might play a role, probably along with other, as yet Posaconazole undetermined factors. The case hereby presented is, to our best knowledge, the first ever reported following mudbaths, although the fungus could have also been introduced by needles used for acupuncture. However, no needle application occurred in close proximity to the area of the lesion. Although the portal of entry of H. capsulatum var. duboisii has not yet been firmly established, it is presumed that, like other Histoplasma spp. it enters the body by the respiratory tract. However, in our case no.