C78.6 — Secondary malignant neoplasm of retroperitoneum and peritoneum
Is C78.6 billable?
Yes — C78.6 is billable for FY2027. C78.6 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. C78.6 may be submitted for encounters from October 1, 2026 through September 30, 2027.
C78.6 at a glance
| Code | C78.6 |
|---|---|
| Description | Secondary malignant neoplasm of retroperitoneum and peritoneum |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does C78.6 group to?
C78.6 sits in MDC 06 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 374Digestive Malignancy with MCCmedical
- 375Digestive Malignancy with CCmedical
- 376Digestive Malignancy without CC/MCCmedical
As a secondary diagnosis, C78.6 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is C78.6 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to C78.6. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Pseudomyxoma peritonei
- Carcinomatosis › peritonei
Excludes1 — never code together — inherited from C78
The conditions below can never be reported together with C78.6 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from C78
The conditions below are not part of C78.6, but a patient may have both at the same time. When documentation supports it, C78.6 and the excluded code may both be reported.
- lymph node metastases (C77.0)
How long has C78.6 existed?
C78.6 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which conditions are coded to C78.6?
What other codes are in the C78 family? (8)
- C78.0Secondary malignant neoplasm of lungnot billable
- C78.1Secondary malignant neoplasm of mediastinum
- C78.2Secondary malignant neoplasm of pleura
- C78.3Secondary malignant neoplasm of other and unspecified respiratory organsnot billable
- C78.4Secondary malignant neoplasm of small intestine
- C78.5Secondary malignant neoplasm of large intestine and rectum
- C78.7Secondary malignant neoplasm of liver and intrahepatic bile duct
- C78.8Secondary malignant neoplasm of other and unspecified digestive organsnot billable