1. Department of Otolaryngology and Clinical Oncology Chair and Clinic of Otolaryngology and Department of Pathophysiology of Hearing and Balance System Collegium Medicum in Bydgoszcz; Nicolaus Copernicus University of Torun; Bydgoszcz Poland
2. Department of Pathomorphology; Collegium Medicum in Bydgoszcz; Nicolaus Copernicus University of Torun; Bydgoszcz Poland
3. Department of Otolaryngology; Oncology Centre; Bydgoszcz Poland
4. Department of Oncologic Pathology; Poznan University of Medical Sciences and Greater Poland, Oncology Center; Poznan Poland