A 10-year observational single-center study of retroperitoneal unicentric Castleman disease.

Diagnosis of unicentric Castleman disease (UCD) is not easy before the resection and obtainment of pathological result. We retrospectively summarized 10-year experience of clinical evaluation and management for retroperitoneal UCD in Peking Union Medical College Hospital (PUMCH) between December 1, 2009 and December 31, 2019. Seventy two UCD patients with pathological diagnosis after resection were screened out. Among them 25 patients had retroperitoneal UCD. The average age of the 25 patients was 43.80 ± 12.79, and 52.00% were male. No patients had systemic symptoms, and 1 patient got preoperative treatment. The average size of masses was 5.59 ± 2.86 cm. The UCD sites included kidney, adrenal area, perinephric area, pancreas, peripancreatic area, area of descending part of duodenum, periaortic area or beside iliac artery, and others. The masses presented different degree of enhancement on CT scans and hypoecho or isoecho on ultrasound. Increased metabolism could be found on 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT). Some patients had positive results on somatostatin receptor imaging, but none had positive results on 131I-metaiiodo-benzylguanidine (131I-MIBG). Some patients presented the elevated level of interleukin-6 (IL-6), 24hour-urinary catecholamine and tumor markers. All the patients received complete resection of masses and 96.00% had hyaline-vascular type pathology except 1 patient (plasma cell-type). Ninety two percent patients received a long-term follow-up with an average follow-up time of 35.48 ± 33.90 months. No patients died or experienced relapse during follow-up. Differential diagnosis of retroperitoneal UCD may be difficult according to imaging and laboratorial examinations. Differential diagnosis with pheochromocytomas/paragangliomas should be taken into special consideration. Different imaging examinations, such as CT/MRI, 18F-PET/CT, somatostatin receptor imaging and 131I-MIBG, can be combined for differential analysis. Complete resection is the best treatment and could provide a final pathological diagnosis.