Secondary and unsp malignant neoplasm of intrathorac nodes

This code signifies the presence of a malignant tumor that has spread to the lymph nodes located within the chest cavity (intrathoracic). It indicates that the cancer originated elsewhere in the body and metastasized to these lymph nodes, or the primary site is unknown.

Use this code when documentation clearly states secondary malignancy of intrathoracic lymph nodes, or when the primary site is unknown but metastasis to these nodes is confirmed. This code is appropriate when the physician explicitly diagnoses metastatic disease to the intrathoracic lymph nodes.

• Always sequence this code after the primary malignancy code, if known.
• If the primary site is unknown, this code can be a principal diagnosis.
• Differentiate from C77.0 (lymph nodes of head, face, and neck) and C77.2 (intra-abdominal lymph nodes) based on anatomical location.