Metastatic tumors are malignant neoplasms that involve the head and neck secondarily through hematogenous spread. The microscopic appearance and genetic profile are those to the primary tumor, and extensive ancillary testing might be required to distinguish cervical lymph node metastasis (CLNM) from non-head and neck primary carcinomas. It is particularly important to screen for primary foci in the lungs, breast, urogenital system, and digestive system after excluding head and neck primary cancers. Molecular profile of the metastatic tumor and comparison with any primary tumor (if available) is desirable. ¹      

The most common neoplastic lesions of the neck are cervical lymph node metastases that originate from a head and neck primary. Important also to be aware that some primary head and neck tumors are known to have overlapping morphological and immunohistochemical features with tumors originating from other organ systems e.g. metastatic breast carcinoma and primary salivary duct carcinoma. ²