ICD-10 Code C54.0 – Malignant neoplasm of isthmus uteri (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C54.0 – Malignant neoplasm of isthmus uteri
What it is
C54.0 identifies a malignant tumor arising in the isthmus of the uterus, the narrow segment between the uterine body and cervix. Use it when documentation specifically names the isthmus as the primary site.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings for uterine malignancy include abnormal vaginal bleeding, pelvic pain, or an abnormal pelvic examination, but the site must be confirmed in the record.
When to use this code
Use C54.0 when the provider documents primary cancer of the uterine isthmus, including pathology or imaging that clearly localizes the tumor there. It is also appropriate when the isthmus is the stated primary site in the final diagnosis or operative note.
If the record only says “uterine cancer” or does not distinguish the exact uterine site, check documentation before assigning this code. You should code the most specific confirmed location available.
Do not use for
Do not use C54.0 for cervical cancer, endometrial cancer without isthmus involvement, or unspecified uterine malignancy. Check documentation if the tumor site is unclear or mixed.
Coding tip
Assign C54.0 only when the isthmus is explicitly documented as the primary malignant site.