Synchronous GISTs associated with multiple sporadic tumors: a case report

Area of Science:

• Gastroenterology
• Oncology
• Genetics

Background:

• Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the GI tract, originating from Cajal cells.
• While often solitary, GISTs can present as multiple tumors, typically in familial cases.
• Sporadic GISTs, usually linked to c-KIT proto-oncogene activation, account for 95% of cases.

Observation:

• A patient presented with primary prostate and lung tumors alongside gastric and small bowel GISTs, unrelated to hereditary syndromes.
• The prostatic tumor preceded the GISTs, while the lung tumor, diagnosed as non-small cell lung cancer, occurred later.
• Gastric and abdominal GIST nodules showed similar MIB1 index and mitotic counts but distinct c-KIT mutations.

Findings:

• Genetic analysis revealed two different c-KIT mutations in the gastric and abdominal GISTs, suggesting synchronous, multicentric origins.
• This molecular heterogeneity is crucial for differentiating synchronous GISTs from metastases.
• The patient is currently disease-free after adjuvant imatinib therapy.

Implications:

• Accurate c-KIT mutational analysis is vital for distinguishing synchronous GISTs from metastases, impacting therapeutic decisions.
• Multidisciplinary team involvement and regular radiological follow-up are essential for detecting GIST recurrence or additional malignancies.
• This case underscores the complexity of GIST presentation and the importance of comprehensive diagnostic approaches.