Oncology & Hematology Coding Alert

See how to report these diagnoses under ICD-9-CM and ICD-10-CM.

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-9-CM index by looking up “tumor,” says Denae M. Merrill, CPC, HCC coding specialist in Saginaw, Mich. Under “tumor,” locate the term “stromal” and then under that find “gastrointestinal,” says Merrill.

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 index points to 238.1 (Neoplasm of uncertain behavior of connective and other soft tissue). You also use this code if the documentation specifies uncertain behavior. In fact, a note with 238.1 specifies it is appropriate for stromal tumors of the digestive system. Under ICD-10-CM, 238.1 crosswalks to D48.1 (Neoplasm of uncertain behavior of connective and other soft tissue).

If the documentation indicates a benign GIST, use 215.5 (Other benign neoplasm of connective and other soft tissue of abdomen). This code’s ICD-10-CM equivalent is D21.4 (Benign neoplasm of connective and other soft tissue of abdomen).

Finally, for a malignant GIST, use 171.5 (Malignant neoplasm of connective and other soft tissue of abdomen). Under ICD-10-CM, the appropriate code is C49.4 (Malignant neoplasm of connective and soft tissue of abdomen).

2. Which Code 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 that has metastasized to another site). However, because this phrasing is unclear, work with the physician to ensure the documentation is precise and provides the information required for accurate coding.

If you confirm this is a secondary carcinoma, choose 197.8 (Secondary malignant neoplasm of other digestive organs and spleen). Under ICD-10-CM, the most likely option is 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 199.1 (Other malignant neoplasm of unspecified site). The ICD-10-CM equivalent is C80.1 (Malignant [primary] neoplasm, unspecified).

In contrast, a primary neuroendocrine carcinoma of the pancreas should be reported using 157.4 (Malignant neoplasm of islets of Langerhans), which crosses to C25.4 (Malignant neoplasm of endocrine pancreas).