Giant GIST: an uncommon cause of acute gastrointestinal bleeding

Gastrointestinal stromal tumours (GISTs) are rare mesenchymal neoplasms. Although most are discovered incidentally, some can develop into large masses with multiorgan involvement. We report the case of a woman in her 50s who presented to the emergency department with acute gastrointestinal bleeding. Physical examination revealed a painless mass in the right lower abdomen. CT demonstrated a large, lobulated mass in the left flank/iliac fossa measuring 15×16×8.5 cm. Exploratory laparotomy revealed a tumour invading two segments of the small intestine, which were resected en bloc. The postoperative course was uneventful and histopathological evaluation revealed a GIST (c-Kit and DOG1 positive). Despite originating within the smooth muscle layers, GISTs may erode the mucosa and cause acute gastrointestinal bleeding, presenting as haemorrhagic shock and requiring urgent surgical intervention. Prognosis depends primarily on tumour location, size and mitotic index. In high-risk cases, adjuvant imatinib therapy is warranted.