Gastrointestinal rectal stromal tumor with hepatic metastases: A case report

Introduction

Gastrointestinal stromal tumors (GISTs) are rare tumors, accounting for approximately 1 % of digestive cancers. Among them, rectal GISTs are unusual (< 5 % of GISTs). Their metastatic form, particularly with liver involvement, is even rarer and poses diagnostic and therapeutic challenges.

Case report

A 73-year-old ASA II patient presented with rectal discharge and mild abdominal discomfort. Colonoscopy revealed a 5.2 × 4.7 cm lesion in the lower rectum, 3 cm from the anal margin. Histological and immunohistochemical analysis confirmed a high-risk spindle cell GIST (mitotic index: 8/50 HPF). Extension workup showed five liver metastases (segments VI–VIII), the largest measuring 3.8 cm. According to AJCC 2017 staging, the patient was classified as Stage IV. After multidisciplinary team discussion including oncologists, surgeons, and radiologists, imatinib therapy (400 mg daily) was initiated. Six-month follow-up showed a 30 % reduction in both primary tumor and metastatic lesions, with continued imatinib therapy and no surgical intervention to date.

Discussion

Metastatic rectal GIST with liver involvement requires a specific therapeutic approach. Imatinib is the reference treatment, enabling disease stabilization in approximately 80 % of cases. Close monitoring is essential, and surgery may be considered for responsive cases. Multidisciplinary management optimizes outcomes, with rectal GIST management differing from other GI locations due to anatomical challenges.

Conclusion

Rectal GIST metastatic to the liver is a complex pathology requiring an individualized strategy. Treatment with imatinib, combined with regular assessment, improves tumor control and prognosis, with some patients achieving long-term disease control exceeding 5 years.