Clinical spectrum of retroperitoneal Castleman disease: retrospective analysis of 59 cases in a single Chinese medical center.

BACKGROUNDS: Castleman disease (CD) is a rare lymphoproliferative disorder. While its general clinical and pathological features are well-described, detailed data on retroperitoneal CD-a diagnostically challenging location-remain scarce. This study characterizes the clinicopathological profile, management, and long-term outcomes of retroperitoneal CD. The aim of this study is to clarify the clinical and therapeutic characteristics of retroperitoneal CD, and to provide practical evidence for its accurate diagnosis and individualized management in clinical practice. METHODS: A retrospective analysis of 59 patients with pathologically confirmed retroperitoneal CD (September 2010-December 2025) was conducted at a single center. Patients were classified as unicentric CD (UCD) or multicentric CD (MCD), with demographic, clinical, imaging, treatment, and follow-up data analyzed. RESULTS: The cohort included 52 UCD and 7 MCD patients. UCD patients were younger (median 38 vs. 56 years, p = 0.021), predominantly female (65.40%), and asymptomatic (65.40%). All MCD patients presented with systemic inflammatory symptoms. Perirenal location was the most common (36.54% of UCD). CT consistently showed well-circumscribed, hypervascular masses with intense arterial enhancement. Complete surgical resection of UCD achieved 100% disease-free survival (median follow-up 98.5 months). Multidisciplinary management (surgery, corticosteroids, or rituximab-based therapy) achieved disease control in all MCD patients. CONCLUSIONS: Retroperitoneal UCD and MCD are distinct entities. UCD, a typically hyaline vascular type, is often incidentally detected and curable by complete surgical excision. MCD, usually plasma cell type with systemic symptoms, requires systemic therapy. Accurate preoperative diagnosis is critical to guide curative surgery for UCD and multidisciplinary management for MCD.