title: Fontana-positive grains in mycetoma caused by Microsporum canis.
abstract: We describe mycetoma caused by Microsporum canis occurring in a 9-year-old African-American girl. Pathologic evaluation showed a granulomatous dermatitis with numerous large fungal grains containing septate hyphae that were Fontana-Masson positive. Two cultures of pure grains grew M. canis. Mycetoma due to dermatophytes is very uncommon. The few instances reported have been pseudomycetoma (grains in the absence of sinus tracts). Our patient developed sinus tracts (true mycetoma). No prior reports were found of M. canis staining Fontana positive. Differentiation of dermatophyte-induced mycetoma from kerion is important because mycetomas require a combined approach including surgical debridement in addition to oral antifungal therapy.
authors.affiliation: Department of Dermatology, Geisinger Medical Center, Danville, Pennsylvania 17822, USA.
authors.forename: Sasha C
authors.initials: SC
authors.lastname: Kramer
authors.forename: Michael
authors.initials: M
authors.lastname: Ryan
authors.forename: Paul
authors.initials: P
authors.lastname: Bourbeau
authors.forename: William B
authors.initials: WB
authors.lastname: Tyler
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Elston
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D008864:Microsporum; D008271:Mycetoma / Q000382:microbiology* / Q000473:pathology* / Q000628:therapy; D012536:Scalp Dermatoses / Q000382:microbiology* / Q000473:pathology* / Q000628:therapy; D012835:Silver Nitrate
chemical_list: C051037:Fontana-Masson stain; D012835:Silver Nitrate