Laryngeal Cytology: A Cytologic, Histologic, P16 and HPV Study

BACKGROUND: Invasive diagnostic methods, such as punch biopsies, have a potential to produce undesirable side effects in the larynx, such as scarring and vocal dysfunction. This study is an attempt to assess the diagnostic potential of cytology to efficiently diagnose premalignant and malignant laryngeal lesions, while sparing patients the risk of complications of punch biopsies. METHODS: Laryngeal smears, using endocervical-type brushes, and punch biopsies were procured from each patient. Smears were prepared and the brush was cut and put in Surepath preservative solution for cytological analysis and human papillomavirus (HPV) DNA testing. A Real-TM Quant kit that detects 14 HPV types was used for genotyping. Immunohistochemical staining for p16 was performed on cytological and histological specimens. RESULTS: Cytological diagnosis was correct in 84.6%, 100% and 100% of cases with a histological diagnosis of squamous cell carcinomas, high-grade squamous intraepithelial lesions and benign lesions, respectively. However, cytological interpretation was correct only in 25% of low-grade squamous intraepithelial lesions. HPV DNA test was positive in only one case, which was a laryngeal polyp. Testing for p16 was negative in all the cytological and histological material. CONCLUSION: Laryngeal cytology is a useful diagnostic tool in establishing the diagnosis of high-grade squamous epithelial cell abnormalities. Recognition of low-grade lesions, however, is challenging. HPV genotyping and p16 staining do not seem to be helpful ancillary techniques in cytological material procured from the larynx.