C54.0
BillableMalignant neoplasm of isthmus uteri
HCC Category Mapping
V28HCC 23 — Melanoma and Other Skin Cancers
0.251V24HCC 12 — Breast, Prostate, and Other Cancers and Tumors
0.150ESRDHCC 12 — Breast, Prostate, and Other Cancers and Tumors
0.000What This Code Means
Cancer that starts in the isthmus uteri, the narrow lower portion of the uterus that connects to the cervix.
Coding Tips
- •Adenocarcinoma is the most common histological type for uterine cancers; document when present
- •Verify whether the tumor is confined to the isthmus or extends into the corpus or cervix for staging purposes
Clinical Significance
Malignant neoplasm of the isthmus uteri involves the narrow transitional zone between the uterine corpus and the cervix. This location is clinically significant because tumors here may have features of both endometrial and endocervical cancers, complicating both staging and treatment planning. The isthmus is sometimes referred to as the lower uterine segment.
Documentation Requirements
- ✓Specific site confirmed as isthmus uteri (lower uterine segment)
- ✓Histological type and grade
- ✓FIGO staging for uterine cancer
- ✓Depth of myometrial invasion
- ✓Cervical involvement assessment (determines stage II vs. stage I)
- ✓Lymph node status
- ✓Lymphovascular space invasion documentation
Commonly Confused Codes
C53.0 — Endocervix; isthmus tumors may extend into the endocervix — determine the primary siteC54.1 — Endometrium; isthmus is the junction between corpus and cervix, distinct from the endometrial cavityC54.9 — Corpus uteri, unspecified; less specific when isthmus is identifiedC55 — Uterus, part unspecified; even less specific
Code Hierarchy
└C54Malignant neoplasm of corpus uteri└C54.0Malignant neoplasm of isthmus uteri
└C54.0Malignant neoplasm of isthmus uteri