Imaging Gigantic Small Bowel Gastrointestinal Stromal Tumours Through Different Radiological Lenses: A Case Report

Gastrointestinal stromal tumours (GIST) account for 1–3% of all the gastrointestinal (GI) neoplasms. It is the most common mesenchymal tumour in the Gl tract. The majority of GISTs are KIT gene positive; however, it is necessary to diagnose them pre-operatively. Here, the authors report the case of a 65-year-old male who presented with pain and a lump in the umbilical region for the last 2 years. On abdominal ultrasound, there was a heterogeneously hypoechoic mass in the umbilical region, with lobulated margins and central necrotic areas. On small bowel series, the core of the mass showed faint contrast opacification. Contrast-enhanced CT of the abdomen showed a heterogeneously enhancing, lobulated exophytic lesion arising from the small bowel loops, the central core of the lesion demonstrating an air-contrast level. Under ultrasound guidance, the lesion was biopsied. Histopathological findings were suggestive of a spindle cell tumour. The sample was c-KIT positive. Hence, the diagnosis of GIST was confirmed. The patient was given imatinib after resection of the mass. Usually, a GIST of larger size has higher malignant and metastatic potential; however, this article shows a gigantic small bowel GIST with cavitation and heterogeneity in different imaging modality, and still has no metastasis on imaging or high mitotic activity, and nuclear atypia on histopathology. A radiologist should also know the imaging pattern on conventional imaging and ultrasound, apart from usual cross-sectional imaging.