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

## TL;DR

This study reviews rare cases of Castleman disease outside lymph nodes, highlighting their locations, treatments, and generally good outcomes after surgery.

## Contribution

The first systematic review of primary extranodal unicentric Castleman disease cases over 20 years, providing comprehensive clinical insights.

## Key findings

- The most common sites were pancreas, adrenal glands, skeletal muscle, parotid glands, and kidneys.
- Surgery provided an 84.6% 4-year recurrence-free survival rate.
- Lymphoma transformation occurred in 2% of cases, emphasizing the need for long-term monitoring.

## Abstract

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.

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.

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.

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.