Retrospective analysis of primary extranodal unicentric Castleman disease: a systematic review

Background: Unicentric Castleman disease (UCD) is a rare lymphoproliferative disorder that typically occurs in lymph node-rich regions. Castleman disease originating in solid organs outside the lymph nodes is extremely rare. Current knowledge is limited to isolated case reports, leaving a lack of systematic evidence to guide diagnosis, management, and prognostic assessment. Methods: We conducted a systematic review of PubMed-reported cases and series of histologically confirmed of primary extranodal UCD over the past 20 years, summarizing their epidemiological, clinical, pathological, therapeutic features and outcome data. Results: A total of 99 cases from 83 publications were included. The median age at diagnosis was 44 years, with a male-to-female ratio of 0.77:1. The mean tumor size was 4.9 cm. The most frequent sites were the pancreas (14.1%), adrenal glands (14.1%), skeletal muscle (14.1%), parotid glands (13.1%), and kidneys (9.1%). Hyaline vascular type predominated (80.8%). Surgery was the primary treatment, yielding a 4-year recurrence-free survival rate of 84.6% (95% CI, 0.512-0.959). Lymphoma transformation occurred in 2% of cases. Radiotherapy and glucocorticoids may be effective treatment options. Conclusion: Primary extranodal UCD displays different anatomic origins but generally carries an excellent prognosis following complete surgical resection. Awareness of its potential for malignant transformation is essential for long-term management.