Dysgerminoma of the ovary presenting as acute abdomen with intratumoural gas image: a diagnostic challenge suspected as a gastrointestinal stromal tumour

A woman in her 20s presented with acute abdomen, manifesting as a palpable abdominal mass, left lower quadrant pain and vomiting. Imaging revealed a large pelvic mass containing multiple linear air pockets, which complicated the differentiation from gastrointestinal tumours (such as gastrointestinal stromal tumour) or abscesses. Emergency surgery revealed a left ovarian tumour with 360-degree torsion and associated congested change. Pathological diagnosis confirmed dysgerminoma, characterised by positive immunohistochemistry for Sal-like protein 4, placental alkaline phosphatase and octamer-binding transcription factor 4 (OCT-4). We hypothesise that the intratumoural gas was intravascular gas associated with the torsion, entrapped within the dysgerminoma's characteristic fibrovascular septa, thereby mimicking an enterogenous mass. This case highlights the importance of considering ovarian torsion as an aetiology of unusual gas images and underscores the challenge in diagnosing rare ovarian malignancies presenting acutely.