# Clinical Presentation, Treatment, and Outcomes of 28 Patients With Castleman Disease: A Retrospective Analysis of an Italian Cohort

## TL;DR

This study analyzes the clinical features and treatment outcomes of 28 Castleman disease patients in Italy, highlighting differences between unicentric and multicentric forms.

## Contribution

The study provides new insights into treatment responses and survival outcomes for distinct Castleman disease subtypes in a single-cohort retrospective analysis.

## Key findings

- Unicentric Castleman disease (UCD) patients had significantly better survival outcomes compared to multicentric subtypes.
- Anti-IL-6 therapy showed partial efficacy in iMCD-NOS patients, with a 30% relapse rate but no deaths.
- Single-agent rituximab was used in HHV-8+ MCD cases, with variable responses observed.

## Abstract

Castleman disease (CD) encompasses a range of heterogeneous non‐clonal lymphoproliferative disorders, including unicentric (UCD), and multicentric (MCD) forms. The latter is subdivided into HHV‐8+ MCD, POEMS‐MCD, and idiopathic‐MCD, not otherwise specified (iMCD‐NOS).

Here we report the clinical characteristics and outcomes of 28 consecutive CD patients, diagnosed in two centers of northern Italy according to recently published diagnostic criteria.

UCD was reported in 12 cases (43%) and MCD in 16 (57%). Among these, 6 (21%) were HHV‐8 positive (1 HIV‐positive and 5 HIV‐negative), and 10 (36%) had iMCD‐NOS. Treatment of UCD consisted of surgical excision in 10/12 cases, resulting in ongoing complete remission in all cases. Single nodal localization favorably affected overall survival (OS) and progression‐free survival (PFS) (p < 0.05). Out of 16 MCD patients, 10 had iMCD‐NOS and 6 had HHV‐8+MCD. Anti‐IL‐6 monoclonal antibody was used as first‐line treatment in 5/10 iMCD‐NOS patients, 3 of whom relapsed, although none died. Two out of 6 patients with HHV‐8+ MCD were treated with single‐agent rituximab and one with rituximab plus chemotherapy. UCD patients had significantly better OS and PFS compared to iMCD and HHV‐8+MCD groups (p < 0.001).

Our report confirms that UCD, iMCD‐NOS, and HHV‐8+MCD represent distinct clinical entities with different outcomes requiring specific treatment approaches.

The authors have confirmed clinical trial registration is not needed for this submission.