Fusarium species have recently emerged as the second most common pathogenic mold in immunocompromised patients, and they are moderately resistant to most antifungal agents. The skin lesions of disseminated fusariosis typically manifest as multiple red or violaceous macules or nodules, often ulcerated and covered by a black eschar. We report a case of cutaneous fusariosis in a patient with long-standing hypopigmented mycosis fungoides. The infection was successfully treated with a 3-month course of oral voriconazole. The present case is unusual in that the infection occurred within a pre-existing, ulcerated lesion of cutaneous CD8+ lymphoma, resulting clinically in confusion with pyoderma gangrenosum and necrosis of lymphoma. A high index of suspicion will prompt a timely biopsy as well as isolation of the fungus, and early institution of systemic antifungal therapy.