Gastrointestinal Stromal Tumor and Ki-67 as a Prognostic Indicator

Area of Science:

• Oncology
• Gastroenterology
• Pathology

Background:

• Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the GI tract, often presenting with nonspecific symptoms.
• Diagnosis typically involves KIT/CD117 and DOG-1 markers, with Ki-67 emerging as a key prognostic indicator for recurrence risk.

Observation:

• A case of a 71-year-old male with a large ileal mesenchymal mass exhibiting pathognomonic GIST features is presented.
• The tumor showed diffuse CD117/c-Kit expression, high-grade spindle cell morphology, a high mitotic rate (30/HPF), and 10% Ki-67 positivity.
• The patient presented with severe symptoms including bloody diarrhea and hemodynamic instability, necessitating surgical intervention.

Findings:

• Immunohistochemical analysis confirmed GIST with high-grade features and significant Ki-67 proliferation index.
• The combination of tumor size, mitotic rate, and Ki-67 expression is crucial for assessing GIST prognosis.
• Surgical resection and targeted therapies like imatinib have significantly improved GIST outcomes.

Implications:

• Ki-67 provides a reliable and reproducible method for evaluating GIST prognosis and guiding treatment decisions.
• Early identification and risk stratification of GISTs are essential for optimizing patient management and improving survival rates.
• This case highlights the importance of comprehensive pathological assessment, including Ki-67, in managing GIST patients.