Chronic Kirschsteiniothelia infection superimposed on a pre-existing non-infectious bursitis of the ankle: the first case report of human infection

Kirschsteiniothelia is a saprophytic fungus that is abundantly present in the environment. To date, there have been no reports of human infection caused by this fungus. We report a case of Kirschsteiniothelia infection superimposed on a pre-existing non-infectious bursitis of the ankle. An 81-year-old immunocompetent female local farmer noticed the presence of a nodule on her right ankle 5 years before her first visit to our hospital. A cystic mass of approximately 45 mm × 30 mm was present at the tip of the right lateral malleolus. Culture of the aspirated fluid revealed visibly black colonies and characteristic blackish hyphae; nucleotide sequence of the internal transcribed spacer region was determined and compared in a GenBank database. The results indicated Kirschsteiniothelia infection. We described the first case of Kirschsteiniothelia infection manifested as ankle bursitis. The disease seemed to be localized and systemic antibiotics had not been used in this case. However, continued observation is needed because of the possibility of disease progression with the pathogen.