General Surgery Coding Alert

Reader Questions:

Focus This Ovarian ‘Borderline’ Tumor Dx

Question: The pathology report for a left oophorectomy identifies “serous tumor of low malignant potential (atypical proliferative serous tumor of ovary).” Would C56.2 be the correct diagnosis code for this case?

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Answer: No, C56.2 (Malignant neoplasm of left ovary) is not the best code for this case

Low malignant potential tumors are also known as borderline tumors according to the American Cancer Society (Source: That means you should not report them as a malignant neoplasm, ruling out any of the following ovarian diagnosis codes:

  • C56.1 (Malignant neoplasm of right ovary)
  • C56.2 (… left ovary)
  • C56.9 (... unspecified ovary).

Instead, you should think of it as a tumor of uncertain behavior, and you should report D39.12 (Neoplasm of uncertain behavior of left ovary) for this case.