Disseminated Cutaneous Leishmaniasis Presenting as Multiple Skin Ulcers Was Misdiagnosed and Treated as Refractory Pyoderma Gangrenosum: A Case Report

<p>A 54-year-old man with a travel history in South America presented at our hospital with an ulcer on his left elbow that initially appeared 3 years earlier. He was initially diagnosed with a nontuberculous mycobacterial infection and received antibiotic treatment at a hospital. Subsequently, he was diagnosed with pyoderma gangrenosum and treated with systemic steroids, immunosuppressive drugs, and TNF-α inhibitors at a different hospital. The ulcers remained unresponsive to treatment, resulting in progressive deterioration of his condition. Due to the immunosuppression, the patient was complicated with invasive pulmonary aspergillosis and underwent a right upper lobectomy. When he arrived at our hospital, he had multiple skin ulcers on his face and trunk, erosions and crusts on the left nasal mucosa and the lip. The skin biopsy specimen from the previous hospital revealed infiltration of dense inflammatory cells, necrotic lesions, granulomatous changes, and kinetoplast-bearing parasites. ELISA using Leishmania protozoan antigen (thiol-specific antioxidant) was strongly positive. PCR analysis of the specimen confirmed the presence of Leishmania infantum, establishing the diagnosis of disseminated cutaneous leishmaniasis. Oral steroids were tapered, and he received liposomal amphotericin B and itraconazole to treat invasive pulmonary aspergillosis, significantly improving his general condition and healing the skin lesions. Although leishmaniasis is one of the Neglected Tropical Diseases and is extremely rare in Japan, his worsened condition was primarily due to iatrogenic complications and delayed diagnosis. Leishmaniasis should be considered as a differential diagnosis in patients with refractory ulcers who have a travel history to endemic area for leishmaniasis. This case emphasizes the importance of a comprehensive evaluation when managing refractory ulcers.</p>