BACKGROUND: Fine needle aspiration biopsy (FNAB) of the skin is useful in subcutaneous lesions. Dermatophytes are almost exclusively superficial cutaneous mycoses and constitute 70-80% of all mycoses and 5% of dermatologic consultations. Inflammatory and invasive forms, as well as infections that remain in chronic forms or persist in spite of treatment, are more frequent in immunocompromised individuals. The clinicalpresentations of these invasive cases are dermatopbytic granulomas (granuloma of Wilson-Majocchi and pseudomycetoma) or Hadida's disease. CASE: A 17-year-old male with an 8-year history of tinea capitis and multiple kerion lesions in the occipital region, left foot and right elbow resistant to conventional treatment was diagnosed by KOH tests and cultures as Microsporum canis. Two months before consultation he noticed the slow growth of a subcutaneous nodule in the base of the neck. FNAB of the neck nodule was performed. The diagnosis of pseudomycetoma by Microsporum canis was made. CONCLUSION: We report a case of pseudomycetoma caused by Microsporum canis, with the diagnosis made by FNAB. This case appears to be the first one diagnosed by this method in a human.
BACKGROUND: Fine needle aspiration biopsy (FNAB) of the skin is useful in subcutaneous lesions. Dermatophytes are almost exclusively superficial cutaneous mycoses and constitute 70-80% of all mycoses and 5% of dermatologic consultations. Inflammatory and invasive forms, as well as infections that remain in chronic forms or persist in spite of treatment, are more frequent in immunocompromised individuals. The clinicalpresentations of these invasive cases are dermatopbytic granulomas (granuloma of Wilson-Majocchi and pseudomycetoma) or Hadida's disease. CASE: A 17-year-old male with an 8-year history of tinea capitis and multiple kerion lesions in the occipital region, left foot and right elbow resistant to conventional treatment was diagnosed by KOH tests and cultures as Microsporum canis. Two months before consultation he noticed the slow growth of a subcutaneous nodule in the base of the neck. FNAB of the neck nodule was performed. The diagnosis of pseudomycetoma by Microsporum canis was made. CONCLUSION: We report a case of pseudomycetoma caused by Microsporum canis, with the diagnosis made by FNAB. This case appears to be the first one diagnosed by this method in a human.