[Retroperitoneal schwannoma mimicking colorectal cancer metastases: a false positive result report.]

schwannomas are benign and common soft tissue tumors. They are usually asymptomatic and are discovered for other reasons.

we present the case of an 82-year-old male patient with a recent diagnosis of moderately differentiated adenocarcinoma of the colon and a hypermetabolic periaortic nodule as an incidental finding.

percutaneous biopsy of the periaortic nodule confirmed the diagnosis of schwannoma. At one year of follow-up, growth of the schwannoma has been demonstrated. There are no signs of progression of his oncological disease.

schwannomas are benign tumors, rarely found in the retroperitoneum and can be sources of false-positive positron emission tomography results.