Cytology and direct human papillomavirus testing on fine needle aspirates from cervical lymph node metastases of patients with oropharyngeal squamous cell carcinoma or occult primary.

OBJECTIVE: Cervical lymph node fine needle aspirates (FNAs) may represent the only specimens available for an initial characterisation of patients with lymphadenopathy. Morphology and human papillomavirus (HPV) DNA presence were evaluated in FNAs collected from patients with oropharyngeal squamous cell carcinoma (OPSCC) or cancer of unknown primary (CUP). FNA HPV results were compared with those of the respective formalin-fixed paraffin-embedded (FFPE) primary cancer.

METHODS: Liquid-based cytology was performed on FNAs collected in PreservCyt. HPV-DNA was analysed by the INNO-LiPA HPV genotyping Extra II on both cytological and FFPE samples. The CINtec® Histology Kit was used to assess p16 expression in cancer tissues.

RESULTS: Forty-seven FNAs were collected from OPSCC and 16 from CUP patients. Cancer cells were found in 35/47 cases (74.5%), while 11 (23.4%) showed only necrosis and one (2.1%) was negative for malignancy. HPV-DNA was detected in 30/47 FNAs (63.8%), mostly harbouring HPV16 (90.0%). An excellent agreement was observed between the FNA and corresponding FFPE HPV status (raw agreement: 97.5%; Cohen κ: 0.94). The HPV test result on the necrotic FNAs completely matched that of the respective primary cancer. FNA HPV testing correctly identified 26/27 HPV-driven OPSCCs (96.3%). HPV was detected in nine of 16 FNAs (56.2%) from CUP patients.

CONCLUSIONS: HPV status of metastatic cervical lymph node FNAs reflects that of the corresponding primary OPSCCs even when cell integrity in the FNA is not preserved and only necrotic debris are present. In patients with initial CUP, HPV-positivity on the FNA may guide the diagnostic workup and therapeutic management, since it suggests an oropharyngeal origin.