Microsphaeropsis arundinis is an anamorphic fungal plant inhabitant belonging to the form class Coelomycetes. We describe two cases of M. arundinis soft tissue infections in immunosuppressed patients. This organism has not previously been described as causing disease in humans. It was identified on the basis of its typical ostiolate pycnidial conidiomata, ampulliform conidiogenous cells, and small, smooth-walled, brown, cylindrical conidia.Members of the class Coelomycetes are emerging as an important group causing soft tissue infections in immunosuppressed patients (13,16). Infections usually are localized, following traumatic implantation, but may progress to invasive subcutaneous disease (2,4,5,7,9,11,17). Airborne transmission of these fungi is unlikely since they typically produce their conidia within enclosed structures known as conidiomata (16). In this report we describe two subcutaneous infections caused by Microsphaeropsis arundinis in diabetic patients.Species of the genus Microsphaeropsis Höhnel are coelomycetous anamorphic fungi that have probable affinities to the ascomycete genus Paraphaeosphaeria O. Eriksson (3). Microsphaeropsis species are typically found as saprobes and parasites of terrestrial plants. They inhabit branches and leaves of various plant hosts and are ubiquitous in soil and freshwater environments.Case 1. An 80-year-old non-insulin-dependent diabetic man presented with a 3-cm-diameter painless, deep granulomatous plaque on the dorsum of the right hand. The lesion had been slowly enlarging over a period of months. Past medical history included ischemic heart disease, chronic renal impairment, and a chronic inflammatory demyelinating polyneuropathy for which he was receiving long-term corticosteroid therapy. A punch biopsy specimen of the lesion was obtained and submitted for fungal culture and histology. Direct fluorescent microscopic examination using a Blankophor BA (Bayer) fluorescent stain revealed irregular, septate hyphae. The treating dermatologist, pending culture results, started treatment with oral terbinafine at standard doses. There was a greater than 50% reduction in plaque size by 12 weeks. Formal excision of the lesion was not required. Terbinafine therapy was ceased, and the lesion resolved over the next 8 weeks. Several months later, the patient developed a bloodstream infection with Candida albicans and received a prolonged course of oral fluconazole for this. There had been no recurrence of the lesion at the time of the patient's death, 2.5 years later.Case 2. A 56-year-old diabetic man was admitted to a hospital for investigation and management of recurring ulcers on both feet. He also had persistent osteomyelitis of the left fourth finger. Medical problems included chronic renal failure requiring hemodialysis and ankylosing spondyloarthropathy, for which he received corticosteroid therapy. His past history was notable for recurrent wound infections of his feet and amputation of two toes 4 years earlier. At the same time, osteomyelitis of the left fourth finger...