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Oncology & Hematology Coding Alert


Find Solutions to Your GIST and Pancreatic Carcinoma Questions Here

See how to figure out what code you should report.

Oncology coding isn’t always cut and dry. Below are two questions from coders in the field, with answers indicating the additional information needed to choose the most appropriate code.

1. What Is the Appropriate Code for GIST?

To find the proper diagnosis code for a gastrointestinal stromal tumor (GIST), start in the ICD-10-CM index by looking up “tumor,” says Kelly C. Loya, CPC-I, CHC, CPhT, CRMA, Associate Partner, Pinnacle Enterprise Risk Consulting Services, LLC. Under “tumor,” locate the term “stromal” and then underneath find “gastrointestinal,” says Loya.

The index then points you to different codes based on the information available in the documentation.

If GIST is the only information you have, the default code is C49.A0 (Gastrointestinal stromal tumor, unspecified site).

If the documentation specifies uncertain behavior, you will turn to code D48.1 (Neoplasm of uncertain behavior of connective and other soft tissue). In fact, a note with D48.1 specifies it is appropriate for stromal tumors of the digestive system.

If the documentation indicates a benign GIST, use D21.4 (Benign neoplasm of connective and other soft tissue of abdomen).

Finally, for a malignant GIST, the index once again leads to C49.A0 (Gastrointestinal stromal tumor, unspecified site) with multiple alternative 5th character options for further information to indicate the specific location of the tumor documented.

2. Which Code is Appropriate for Metastatic Neuroendocrine Pancreas Carcinoma?

Suppose your documentation shows “metastatic neuroendocrine carcinoma of the pancreas (islet cell tumor).”

Providers may use “metastatic carcinoma” to indicate a secondary neoplasm resulting from metastasis (rather than indicating a primary neoplasm has metastasized to another site). However, because this phrasing is unclear, work with the physician to ensure the documentation precisely identifies the information required to code accurately.

If a secondary carcinoma is confirmed, choose C78.89 (Secondary malignant neoplasm of other digestive organs).

When reporting a secondary neoplasm code, you should report a code for the primary neoplasm, as well. If the primary site is not identified, report C80.1 (Malignant [primary] neoplasm, unspecified).

In contrast, if the site is not secondary, a primary neuroendocrine carcinoma of the pancreas should be reported using C25.4 (Malignant neoplasm of endocrine pancreas).

Editor’s Note: Still have questions or have your own ICD-10-CM conundrum? Email the editor at