C7A.023

Malignant carcinoid tumor of the transverse colon

FY2027Chapter 2: Neoplasms/C7A Malignant neuroendocrine tumors

BillableComplete code, valid to report

C7A.023 (also written C7A023) is a billable ICD-10-CM diagnosis code for malignant carcinoid tumor of the transverse colon. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 23 codes in category C7A (Malignant neuroendocrine tumors). The Alphabetic Index lists it under 1 entry. Its coding notes include a Use additional code instruction, a Code also instruction and 2 Excludes2 entries.

Use additional code

Add the listed code as a secondary code, if known.

Inherited from C7A Malignant neuroendocrine tumors
  • code to identify any associated endocrine syndrome, such as:

Code also

Two codes may be needed to describe the condition. This note gives no sequencing order.

Inherited from C7A Malignant neuroendocrine tumors
  • any associated multiple endocrine neoplasia [MEN] syndromes (E31.2-)

Excludes2

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

Inherited from C7A Malignant neuroendocrine tumors
  • malignant pancreatic islet cell tumors (C25.4)
  • Merkel cell carcinoma (C4A.-)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Home Health Primary

Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Infectious Disease, Neoplasms, and Blood-Forming Diseases clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 40 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

IPF Comorbidity

On the CMS IPF comorbidity list.

Comorbidity categoryFactor
Oncology Treatment1.44
It counts as a comorbidity when reported as a secondary diagnosis and actively treated during the stay. An IPF receives only one adjustment within a category and can receive adjustments in more than one category.

Source: CMS IPF PPS FY 2027 final rule (CMS-1847-F), Addendum B-3 (comorbidity codes with adjustment factor); effective for discharges on or after October 1, 2026

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).

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry