Cervical Lymph Node Metastasis of Unknown Origin and Remote Primary at a Tertiary Cancer Centre in North India: Case Series with Review of Literature.

Carcinoma of unknown primary site represents a heterogeneous group of malignancies that present with lymph node or distant metastases, for which diagnostic work-up fails to identify the site of origin. Their incidence relative to total head and neck cancers ranges from as low as 1.7 to 2.5%. Malignant cervical lymphadenopathy is occasionally caused by neoplasms from primary sites outside the head and neck region. Here we present a case series of patients diagnosed with cervical lymph node metastasis of unknown origin(MUO neck) and that of remote areas. Electronic database was searched for cases of cervical lymph node metastasis, that were operated or underwent any type of biopsy from August 2018 till February 2024. Details of patients diagnosed with neck metastasis of unknown origin and remote primary were compiled in the form of case series. The incidence of neck metastasis of unknown origin was found to be 1.1%. Two cases of cervical lymph node metastasis from the sites outside the head and neck were found, out of which one case was of breast cancer while the other was cholangiocarcinoma. IHC has a significant role to play in all these conditions. Pointing out exact tumor histology shall open avenues for specific targeted therapy in these metastatic settings.