Deep fungal co-infection with Trichosporon asahii and Candida parapsilosis in an immunocompetent individual: a case report and review of literature

Deep fungal infections are endemic to tropical and subtropical regions and can occur in individuals who are both immunocompetent and immunocompromised. Clinically, these infections may present as verrucous plaques, subcutaneous nodules, abscesses or ulcerations. Common causative organisms in immunocompetent hosts include Sporothrix schenckii, Madurella mycetomatis and Fonsecaea pedrosoi. However, emerging evidence suggests that Trichosporon asahii and Candida parapsilosis are increasingly implicated in these infections. A 64-year-old Cambodian man with a history of recently treated pulmonary tuberculosis, hypertension, diabetes mellitus and untreated adrenal insufficiency presented with three painful leg ulcers on his bilateral lower extremities, with one at the site of prior trauma. Physical examination was remarkable for one 2.5-cm ulcerated plaque over his right patella and two 1-cm ulcerated plaques on both lower legs. Tissue cultures demonstrated moderate growth of both T. asahii and C. parapsilosis. Clinically, deep fungal infections caused by either organism have presented with various morphologies, including erythematous patches and plaques, abscesses and verrucous plaques with ulceration. However, the presentation as an ulcerative plaque is rare, with only four prior cases reported in the literature. In all previously reported cases of deep fungal infections caused by either organism, only one organism was isolated, unlike our patient, where both organisms were identified. This case highlights the importance of maintaining a broad differential for patients presenting with ulcerative plaques and considering deep fungal infection as a potential diagnosis, especially when the lesions are unresponsive to antibiotics.