Schnitzler’s metastasis from gastric carcinoma: A multimodality imaging case report

Schnitzler’s metastasis – haematogenous or lymphatic spread of gastric carcinoma to the rectal wall – is a rare entity that radiologically closely mimics primary rectal adenocarcinoma, creating a risk of misdiagnosis and inappropriate treatment. A 57-year-old woman presented with progressive constipation, tenesmus and rectal discomfort. Contrast-enhanced CT demonstrated circumferential gastric wall thickening, alongside circumferential rectal wall thickening with avid mucosal enhancement. Pelvic MRI revealed submucosal rectal wall thickening with preserved mesorectal fat planes and no significant diffusion restriction. Endoscopic biopsy confirmed metastatic adenocarcinoma of gastric origin. Contribution: Schnitzler’s metastasis should be considered in any patient with upper gastrointestinal malignancy presenting with rectal symptoms. Combined CT and pelvic MRI can assist in accurate characterisation, extent assessment and identification of the gastric primary.