ICD-10 Code C56.9 – Malignant neoplasm of unspecified ovary (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C56.9 – Malignant neoplasm of unspecified ovary
What it is
C56.9 identifies a malignant tumor arising in the ovary when the specific ovary is not documented. Use it for ovarian cancer cases where laterality or exact site is unavailable.
Clinical signs
Clinical features vary; refer to documentation. Ovarian malignancy is often associated with pelvic or abdominal mass, bloating, pain, or nonspecific gastrointestinal symptoms, but diagnosis must be supported by provider documentation.
When to use this code
Use C56.9 when the record clearly states ovarian cancer or malignant neoplasm of the ovary and does not specify right or left side. It also fits when the provider documents a malignant ovarian tumor without further anatomic detail. If laterality is available elsewhere in the chart, code that more specific option instead.
Do not use for
Do not use this code for benign ovarian masses, borderline tumors, or metastatic disease to the ovary from another primary site. Check documentation if the diagnosis is uncertain or the ovary is not the primary site.
Coding tip
Verify whether the note, pathology report, or operative report names the right or left ovary before defaulting to unspecified.