Disseminated blastomycosis with cutaneous involvement in a Canadian railroad worker

Abstract

A 42-year-old man presented presented to a teaching hospital in Toronto in June, 2014, with a 7 month history of progressive verrucous plaques on his chin (fi gure). He had seen many diff erent doctors and been given topical corticosteroid, antifungal, and antibacterial treatment without improvement. He also reported an intermittent cough productive of white sputum and mild dyspnoea on exertion for the past 2 months. Physical examination was normal apart from the skin lesions. Chest radiograph and CT (fi gure) showed multiple large cavitations in the upper lobes (arrows) and tree-in-bud opacities. A biopsy sample of the skin lesions showed broad-based budding yeast with Gomori methenamine silver stain in the dermis consistent with blastomycosis (fi gure, appendix). Fungal culture from a bronchoalveolar lavage grew Blastomyces dermatitidis. The patient reported living in Kenora, Ontario, a region of Canada that is hyperendemic for B dermatitidis 17 years earlier, where he had worked repairing railroad tracks. B dermatitidis is a dimorphic fungus endemic to the St Lawrence–Great Lakes and Mississippi river systems in North America. Cases have also been reported in Africa and the Middle East. The fungus is generally acquired through exposure to soil or moist organic debris and primarily aff ects the lower respiratory tract causing acute or chronic pneumonia. After seeding the respiratory tract B dermatitidis disseminates haematogenously to extrapulmonary sites in 20–50% of cases, most often to the skin, bones, and joints. Primary cutaneous inoculation can also occur. Reactivation of latent disease has been described and might explain our patient’s presentation. Cutaneous blastomycosis is characteristically a verrucous “wart-like” lesion with irregular borders. Ulcerative lesions with raised borders are also common. Any patient with cutaneous blastomycosis should be investigated for pulmonary involvement and other sites of dissemination. We started our patient on 6 months of 200 mg itraconazole twice daily. At 5 month follow-up in November, 2014, the patient is doing well, with no respiratory symptoms and improvement in the skin lesions. Lancet 2015; 385: 883