Mycetoma of the foot caused by Cylindrocarpon destructans

A 39-year-old male, originally from Antigua, West Indies, presented with a 12-year history of swelling of the left foot. A pathogen could not be recovered in cultures of three surgical biopsy specimens. During follow-up, pus and grains were expressed from a draining sinus tract and Cylindrocarpon destructans grew in pure culture. Retrospective examination of histologic sections of tissue removed during the third biopsy demonstrated a grain characteristic of eumycotic mycetoma. Although the fungus was susceptible to amphotericin B and ketoconazole in vitro, the patient refused treatment, and the clinical course over almost 19 years has been one of slow but progressive bone destruction. The fungus was identified by its microconidial morphology, the presence of chlamydospores, and an intense brown diffusible pigment. It was compared with another poorly known agent of white grain mycetoma, Phialophora cyanescens, characterized by phialidic conidia, chlamydospores in aggregations, and an intense diffusing pigment. The new combination Cylindrocarpon cyanescens (de Vries et al.) Sigler comb. nov. is proposed.