Question: Which diagnosis codes should I report when a patient presents for radiation therapy treating squamous cell carcinoma of the posterior hypopharyngeal wall as well as metastasis to cervical lymph nodes? Alabama Subscriber Answer: You need to list the radiation therapy encounter first (V58.0, Encounter for other and unspecified procedures and aftercare; radiotherapy). Because treatment is directed at both the primary malignancy and the metastatic sites, you should code both: " 148.3 -- Malignant neoplasm of hypopharynx;posterior hypopharyngeal wall " 196.0 - Secondary and unspecified malignant neoplasm of lymph nodes; lymph nodes of head, face,and neck.