The Deceptive Glow: FDG-Avid Gastric Mass on PET-CT

Gastric schwannoma is a rare benign peripheral nerve sheath tumour that may closely mimic gastric malignancy on 18 F fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) due to unexpectedly intense radiotracer uptake. We describe a 50-year-old female presenting with iron deficiency anaemia and upper gastrointestinal bleeding. Endoscopy revealed a submucosal gastric mass with an excavated ulcer. FDG PET-CT demonstrated a well-defined exophytic gastric lesion with marked FDG avidity, raising a strong suspicion for malignancy such as gastric carcinoma or high-risk gastrointestinal stromal tumour (GIST). Surgical excision was performed, and histopathology confirmed a gastric schwannoma. Follow-up PET-CT showed no residual or recurrent disease, emphasising a well-recognised PET pitfall wherein benign gastric schwannomas may simulate aggressive malignancy. Thus, intense FDG uptake in a gastric mass should not be considered synonymous with malignancy. Gastric schwannomas may demonstrate substantial FDG avidity and closely mimic malignant gastric neoplasms on PET/CT, necessitating histopathological and immunohistochemical confirmation.