ICD-10 Code C57.21 – Malignant neoplasm of right round ligament (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C57.21 – Malignant neoplasm of right round ligament
What it is
C57.21 identifies a malignant tumor arising in the right round ligament. Use it when documentation specifies a primary cancer or malignant neoplasm in that anatomic site.
Clinical signs
Clinical features vary; refer to documentation. Findings may include a pelvic or groin mass, pain, or imaging evidence of a suspicious lesion, but confirmation depends on the recorded diagnosis.
When to use this code
Use this code when the provider documents malignant neoplasm of the right round ligament, including pathology, operative, or imaging reports that clearly name the site. Code it for the right side only when laterality is stated. If the record is unclear about origin or side, check documentation.
Do not use for
Do not use this code for benign round ligament lesions, nonspecific pelvic masses, or malignancies documented in a different structure. If the chart says “round ligament” without laterality or malignancy, check documentation.
Coding tip
Verify both malignancy and right-sided location in the source note before assigning C57.21.