Abstract
GI stromal tumors (GISTs) are the most common mesenchymal neoplasms in the GI tract. GISTs are malignancies that typically originate in the digestive system, most often in the stomach and small intestine. Histopathological classification identifies three types of GISTs: spindle cell, epithelioid, and mixed. We present a case of a huge intra-abdominal retroperitoneal mass in a 23-year-old female with no notable medical or surgical history. She experienced dysphagia and early satiety for one year but did not seek medical attention until presenting at our clinic. Her abdomen was distended, soft, and firm, with a huge non-tender mass. Abdominal CT revealed a substantial left retroperitoneal soft tissue lesion measuring 17 × 12 × 21 cm, causing a significant mass effect. An exploratory laparotomy via a thoracoabdominal approach was performed. A definitive diagnosis required surgical intervention or tissue biopsy. This case highlights the rarity of spindle cell neoplasms and underscores the importance of maintaining a high index of suspicion for such tumors in young adults.