Head and neck carcinoma of unknown primary.

In adult cervicofacial pathology, carcinoma of unknown primary is defined as lymph-node metastasis the anatomic origin of which is not known at the time of initial management. It constitutes up to 5% of head and neck cancers. Presentation may suggest benign pathology, delaying and confusing oncologic treatment. Diagnostic strategy in cervical lymph node with suspicion of neoplasia requires exhaustive work-up to diagnose malignancy and, in 45% to 80% of cases, depending on the series, to identify the primary site. Histologic types comprise squamous cell carcinoma, thyroid carcinoma, adenocarcinoma, neuroendocrine carcinoma and undifferentiated carcinoma. Association is sometimes found with human papilloma virus or Epstein Barr virus, guiding treatment. The objective of the present study was to provide clinicians with the necessary diagnostic tools, based on the current state of clinical, imaging and pathologic knowledge, and to detail treatment options.