I'm looking for

All Resources

Coding for Bilateral Ovarian Cancer: ICD-10 Coding Updates | Bridget Toomey, MS, CPC, CPB, CPPM, CPCO, AAPC Fellow

Nov 10, 2021

Bridget Toomey, MS, CPC, CPB, CPPM, CPCO, AAPC Fellow

While most ovarian cancers are bilateral, ICD 10 terminology has not previously included a bilateral ovarian cancer code.  This was appealed by the SGO Coding and Reimbursement Subcommittee.  Each year, the Centers for Medicare & Medicaid Services (CMS) releases documents outlining new, deleted, and revised ICD-10 codes to become effective the new fiscal year starting each October.  The FY22 updates effective Oct. 1, 2021 include 159 additions, 25 deletions, 27 revisions, and several general coding guideline updates.

There are two new diagnosis codes specific to bilateral ovaries for both primary and secondary malignancy. SGO coding committee requested these additions back in 2019 and we have been heard!

  • C56 Malignant neoplasm of ovary
    • C56.1 Malignant neoplasm of right ovary
    • C56.2 Malignant neoplasm of left ovary
    • C56.3 Malignant neoplasm of bilateral ovaries – New Code
    • C56.9 Malignant neoplasm of unspecified ovary

The laterality of an ovarian cancer is best assigned by the Gynecologic Oncologist. These codes assign the site of the primary, not the sites of metastatic disease.  Most often ovarian cancers are advanced and bilateral.  The new code allows that to be recorded.  The unspecified code should rarely be used:  if there is enough data to make the diagnosis of an ovarian cancer then the side(s) will generally be apparent as well.


  • C79 Secondary malignant neoplasm of other and unspecified sites
    • C79.6 Secondary malignant neoplasm of ovary
      • C79.60 Secondary malignant neoplasm of unspecified ovary
      • C79.61 Secondary malignant neoplasm of right ovary
      • C79.62 Secondary malignant neoplasm of left ovary
      • C79.63 Secondary malignant neoplasm of bilateral ovaries – New Code

These are the codes used when there is metastatic disease in one or both ovaries. The appropriate code for the site of the primary cancer (e.g. breast, colon) may also be added.


To see details on all ICD-10-CM changes effective Oct. 1, 2021, visit the CMS website.


Bridget Toomey, MS, CPC, CPB, CPPM, CPCO, AAPC Fellow, is the assistant director of clinical operations in the department of Obstetrics and Gynecology at the University of Iowa Health Care.