[Molecular biological identification of fungal pathogens in FFPE tissue from cases of cephalic mycosis]. / Molekularbiologischer Erregernachweis aus FFPE-Proben bei zephaler Mykose.

ABSTRACT

BACKGROUND: Due to the lack of histopathological differentiation the unequivocal identification of fungal pathogens is rarely possible. In order to understand the pathogen spectrum causing cephalic mycosis the use of alternative methods is essential. MATERIAL AND METHODS: In a retrospective study 24 formalin-fixed, paraffin-embedded (FFPE) samples from patients with histologically confirmed cerebral or cephalic mycosis were analyzed with molecular biological methods. RESULTS: In two samples obtained during the patients' lifetime human as well as fungal DNA was detected, making an unambiguous diagnosis possible. For tissue that had been fixed over a longer period, detection of human and fungal DNA was possible merely in 60% and 47 % of the samples, respectively. Most frequently diagnosed were aspergillosis (n = 9), followed by mucormycosis (n = 2) and imported blastomycosis (n = 1). CONCLUSIONS: Using biopsy material a DNA analysis seems promising although only with limited success using brain samples taken at autopsy which have been fixed over a longer period. For unambiguous retrospective diagnostics of pathogens when cephalic mycosis is suspected, the sample extraction for postmortem diagnostics should be performed prior to a long period of formalin fixation.