Missed retroperitoneal fibrosis in a gastric adenocarcinoma patient − A case report

Retroperitoneal fibrosis is a rare condition that is characterized by fibrotic tissue presentation in the retroperitoneal space, usually leading to ureteral obstruction. It is often idiopathic yet a subset of cases is secondary to a malignancy. We report the case of a 72year-old female, that was diagnosed with gastric adenocarcinoma and incidentally found to have retroperitoneal fibrosis on imaging (MRI abdo-pelv). The patient presented with extreme RUQ pain, nausea, vomiting, decreased per os (PO) intake, and minimal weight loss over the past 9 months prior to presentation.Subsequent evaluation confirmed the diagnosis of gastric adenocarcinoma, and upon multiple imaging modalities she was found to have retroperitoneal fibrosis. She doesn’t have a history of an autoimmune or any drug inducing cause. This case highlights the rare occasion of having retroperitoneal fibrosis whilst having an underlying gastric adenocarcinoma. Early recognition helps in better staging, prognosis and the different management strategies.