[HPV-associated oropharyngeal carcinoma. Status quo and relationship with cancer of unknown primary].

Carcinomas of the oropharynx with association to high-risk types of human papillomavirus (HPV) have been identified as a new tumour entity with favourable prognosis, distinct from classical nicotine- and alcohol-associated carcinoma. They develop through oncogenic transformation of the basal cells of reticulated cryptal epithelium of the palatinal tonsils and the base of the tongue. Positivity for HPV strongly correlates with an atypical, non-keratinizing histological differentiation and cystic transformation of lymph node metastases. Strong immunohistological positivity for p16 reliably detects transcriptionally active infection with high-risk HPV. Hence, p16 staining has been regarded as an effectual diagnostic tool in the appropriate setting. Frequent nodal metastasation as well as considerable size of (cystic) metastases, and frequent small size as well as submucosal location of primary tumours all contribute to frequent initial manifestation of cervical cancer of unknown primary (CUP). In a situation of CUP diagnostic testing for HPV (in negative cases in addition to EBV) is recommended in lymph node metastases, due to the high predictive value for the localization of occult primary carcinomas. Intense clinicopathological cooperation is mandatory for improved detection of small, occult primary carcinomas. The relevance of this new carcinoma entity will increase, as the incidence continues to increase worldwide.