Pathology/Lab Coding Alert

Consider “behavior” to pick the right code.

Test your diagnosis-coding prowess for the following surgical pathology case that involves a gastrointestinal stromal tumor (GIST). Decide what ICD-10-CM code you would assign, then turn to “Check Your GIST-Case Diagnosis Code” in the next article to compare your answer with our experts.

Specimen: Small Intestine Segmental Resection for Tumor

Findings:

• Tumor invading full thickness of bowel wall, 9.5 cm greatest dimension
• Resection margins negative for tumor
• Microscopic examination identifies predominately spindle cell type with secondary epithelial cell type
• Mitotic rate: 12 per 50 high power fields
• Histologic grade G2
• Immunohistochemistry:​​
  o Positive for DOG1 and Ki-67
  o Negative for KIT and CD34

Diagnosis: Gastrointestinal Stromal Sarcoma.