C19

Billable

Malignant neoplasm of rectosigmoid junction

HCC Category Mapping

V28HCC 22 — Colorectal, Bladder, and Other Cancers

0.000

V24HCC 11 — Colorectal, Bladder, and Other Cancers

0.306

ESRDHCC 11 — Colorectal, Bladder, and Other Cancers

0.000

What This Code Means

Cancer that occurs at the rectosigmoid junction, which is the area where the sigmoid colon meets the rectum.

Coding Tips

•This code is used when the tumor involves the junction between sigmoid colon and rectum
•Verify documentation confirms involvement of the junction area rather than just one segment

Clinical Significance

Malignant neoplasm of the rectosigmoid junction is clinically significant because tumors at this boundary zone between the sigmoid colon and rectum may require treatment approaches from both colon and rectal cancer paradigms. The rectosigmoid junction is defined as the area approximately 12-15 cm from the anal verge, and cancers here may be managed with either low anterior resection or sigmoid colectomy depending on exact location and extent. Accurate coding at this specific junction affects treatment decisions and resource allocation.

Documentation Requirements

✓Documentation confirming the tumor involves the rectosigmoid junction specifically
✓Distance from the anal verge if measured (typically 12-15 cm)
✓Histological type and grade
✓Stage of disease with circumferential resection margin status
✓Whether neoadjuvant chemoradiation was administered (more common for rectal-predominant tumors)

Excludes 1 — Do NOT code together

malignant carcinoid tumors of the colon (C7A.02-)

Commonly Confused Codes

C18.7 — Sigmoid colon: if the tumor is entirely in the sigmoid without extending to the rectum, use C18.7 C20 — Rectum: if the tumor is entirely rectal without sigmoid extension, use C20 C21.8 — Overlapping sites of rectum/anus/anal canal: use when the tumor extends below the rectum to involve anal structures

Code Hierarchy

└C19Malignant neoplasm of rectosigmoid junction

C19