Oncology & Hematology Coding Alert

See how you'll navigate terminology in the Alphabetic Index.

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?

GIST is defined as a gastrointestinal stromal tumor. To find the proper diagnosis code for GIST, start in the ICD-10-CM index by looking up "tumor." Under "tumor," locate the term "stromal" and then find "gastrointestinal." The index 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 C49.A- (Gastrointestinal stromal tumor). Keep in mind: You will still need a fifth character, but without any additional information, report C49.A0 (...unspecified site).

Underneath the gastrointestinal determination in your Alphabetic Index, you've got additional options if the information is available in the documentation.

Benign: For instance, if the documentation indicates a benign GIST, you'll use D21.4 (Benign neoplasm of connective and other soft tissue of abdomen). GIST includes tumors of the GI system. However, it is important to note 'stromal tumors' could occur at other anatomical sites. If the site is not gastrointestinal, look for the correct site to classify the tumor. For stromal tumors at other locations, search in the neoplasm table for main term connective tissue NEC. Then find the appropriate sub term (location) for your code in the column labeled Benign. Always follow up by looking up the code in the tabular list.

Esophagus: For a GIST of the esophagus, you'll turn to C49.A1 (Gastrointestinal stromal tumor of esophagus).

Large intestine: For a GIST of the large intestine, check out C49.A4.

Malignancy: For a malignant GIST, you've got a bevy of options. For malignant GIST, highlight C49.4 (Malignant neoplasm of connective and soft tissue of abdomen). But you can go deeper into specific anatomical sites, including:

• Colon (C49.A4)
• Duodenum (C49.A3)
• Esophagus (C49.A1)
• Ileum (C49.A3)
• Jejunum (C49.A3)
• Large intestine (C49.A4)
• Meckel diverticulum (C49.A3)
• Omentum (C49.A9)
• Rectum (C49.A5)
• Small intestine (C49.A3)
• Specified site NEC (C49.A9)
• Stomach (C49.A2).

Rectum: If the GIST is of the rectum, you can look at C49.A5.

Small Intestine: Again, you'll turn to C49.A3.

Specified site NEC: You'll choose C49.A9.

Stomach: Again, report C49.A2.

Uncertain behavior: GIST of uncertain behavior directs you to D48.1 (Neoplasm of uncertain behavior of connective and other soft tissue).

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 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, a primary neuroendocrine carcinoma of the pancreas should be reported using C25.4 (Malignant neoplasm of endocrine pancreas).