Alphabetic Index FY2027

C78

Secondary malignant neoplasm of respiratory and digestive organs

FY2027Chapter 2: Neoplasms/C76–C80 Malignant neoplasms of ill-defined, other secondary and unspecified sites

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

C78 is a non-billable ICD-10-CM code category for secondary malignant neoplasm of respiratory and digestive organs. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are C78.0 Secondary malignant neoplasm of lung, C78.1 Secondary malignant neoplasm of mediastinum, C78.2 Secondary malignant neoplasm of pleura, C78.3 Secondary malignant neoplasm of other and unspecified respiratory organs and 5 more. Its coding notes include 2 Excludes1 entries and 1 Excludes2 entry.

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

When treatment is directed only at the metastatic site, the secondary site is first-listed and the primary malignancy is an additional code.

Guidelines I.C.2.l.2Treatment directed at a secondary siteRead the official text

Excludes1

Not coded here. The listed conditions generally should not be reported together.

This code
  • secondary carcinoid tumors of liver (C7B.02)
  • secondary carcinoid tumors of peritoneum (C7B.04)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

This code
  • lymph node metastases (C77.0)

Notes

Also from chapter/block level (8 notes)
Inherited from Chapter 2 Neoplasms
  • Functional activity
  • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
  • Morphology [Histology]
  • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
  • Primary malignant neoplasms overlapping site boundaries
  • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
  • Malignant neoplasm of ectopic tissue
  • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

More specific codes under C78 9