Oncology & Hematology Coding Alert

Question: I am trying to code leiomyosarcoma of the sigmoid colon. I have found documentation stating if the leiomyosarcoma has originated in an organ, then it should be coded to the site. However, the provider is insisting that it should be coded to connective tissue. How should I code it?

AAPC Forum Participant

Answer: In this case, your provider is correct. Here’s why.According to the National Cancer Institute, leiomyosarcoma (LMS) is “a type of rare cancer that grows in the smooth muscles. The smooth muscles are in the hollow organs of the body, including the intestines, stomach, bladder … blood vessels … [and] the uterus” (www.cancer.gov/pediatric-adult-rare-tumor/rare-tumors/rare-soft-tissue-tumors/leiomyosarcoma).

This makes LMS a soft, or connective, tissue sarcoma. Per the ICD-10-CM Alphabetic Index, LMS is coded to Neoplasm, connective tissue, malignant, which is consistent with the note in the neoplasm table that tells you to code neoplasms of connective tissue according to the list under ‘Neoplasm, connective tissue’ and “code to neoplasm of that site” for “sites that do not appear in this list.”

As Neoplasm, connective tissue, intestinal, malignant appears on the list and can be coded to C49.4 (Malignant neoplasm of connective and soft tissue of abdomen), that is the code you should use rather than coding the neoplasm to the site, which would be C18.7 (Malignant neoplasm of sigmoid colon).