[Incidentally discovered retroperitoneal unicentric Castleman disease during an ischemic colitis episode and diagnosed by computed tomography-guided needle biopsy: a case report].

A 30-year-old female patient had an 8-cm retroperitoneal mass that was incidentally discovered during an abdominal computed tomography (CT) scan performed for diagnosing ischemic colitis, resulting in her referral to our hospital. A CT-guided needle biopsy was performed with a 20G needle, but the results were inconclusive. A 14G needle was used after weighing the benefits and harms, resulting in the diagnosis of a hyaline-vascular variant of Castleman disease. No laboratory or imaging features are specific for unicentric Castleman disease, and abdominal occurrence has been rare. However, the number of cases found as abdominal masses has been increasing in recent years. The characteristic pathological findings need to be carefully examined.