This paper communicates the presence of aberrant microscopic forms of Histoplasma capsulatum in a sample ob-tained by scrapping of the skin lesion and stained with a rapid modification of the Grocott technique.The AIDS patient was treated with cream contained corticoids and antifungal and antibacterial antibiotics by an erroneous diagnosis.Once the etiologic diagnosis was achieved,oral itraconazol was administrated at the daily dose of 400 mg during at least six months.These non habitual forms described in the literature asaberrant variants, can be interpreted as anadaptive phenomenonof this termodimorphic fungal specie,as response of the eco-logic alterations produced by antibiotic on the local antagonic bacterial microbiota,the deleterous activity of antifungal on the fungal cells and the local inmunodepression produced by the corticoids.