We have a patient referred for metastatic lung cancer for radiation therapy. Bx was performed and came back s suspicious for metastatic melanoma with strongly positive S100 and SOX10 showing weak staining with Melan A. Origially coded as C78.01. From a coding standpoint, what is the difference between code C43.9 and C78.01? Both have refernces to including Secondary malignancy to the lung. Since there is no outward clinical evidence of there being Melanoma to the Eyes or Skin which would be the more appropriate code to use?

Thank you.

GQuinn