Rectal Gastrointestinal Stromal Tumour: A Report of a Rare Case and Literature Review.

Gastrointestinal stromal tumours (GISTs), are an extremely uncommon form of different types of gastrointestinal (GI) malignant neoplasms. While GISTs are the most prevalent type of mesenchymal tumours in the GI tract, they are mainly located in the stomach. Gastrointestinal stromal tumours in the rectum are rarely observed. Some individuals may exhibit symptoms such as constipation, pain in the rectum, bleeding per rectum, or palpable growth, while others may be discovered incidentally. The prevalence of GISTs has been increasing, potentially as a result of developments in imaging techniques. In the present case report, we describe a 47-year-old male patient who initially complained of pain in the lower abdomen, rectum, and occasional constipation. A contrast-enhanced CT (CECT) scan revealed a well-defined hypodense, enhancing lesion with a small calcified area at its periphery in the rectum. The lesion caused a significant luminal narrowing of the rectum. During colonoscopy, a mass located in the submucosal region was identified on the side of the rectal wall, approximately 1 cm away from the anus. After performing the biopsy, the specimen was subjected to histological examination, which revealed a spindle cell tumour with a mild cellular appearance. This finding was in line with the diagnosis of a GIST located in the rectum. The purpose of the current case report is to highlight the significance of CT, colonoscopy, and biopsy in promptly identifying rare GISTs in the colon and rectum, emphasising the uncommon occurrence of GISTs along with their typical locations and imaging features.