C78.3
Secondary malignant neoplasm of other and unspecified respiratory organs
Not billable — category only FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 8 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 3 never code together
C78code
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 8
C00-D49chapter
Notes
- 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).C25.9
Index entries leading here filed at null
No alphabetic index entry points at this code.
Alongside this code 8 same parent — C78
C78.0 Secondary malignant neoplasm of lung category C78.1 Secondary malignant neoplasm of mediastinum C78.2 Secondary malignant neoplasm of pleura C78.4 Secondary malignant neoplasm of small intestine C78.5 Secondary malignant neoplasm of large intestine and rectum C78.6 Secondary malignant neoplasm of retroperiton and peritoneum C78.7 Secondary malig neoplasm of liver and intrahepatic bile duct C78.8 Secondary malignant neoplasm of and unsp digestive organs category
Subordinate codes 2
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.