# Two Cases of Systemic Lupus Erythematosus With Castleman Disease

## TL;DR

This paper reports two rare cases where systemic lupus erythematosus co-occurred with Castleman disease, both successfully treated with rituximab.

## Contribution

The paper presents two new clinical cases of a rare association between systemic lupus erythematosus and plasma cell-subtype Castleman disease.

## Key findings

- Two Latin-American women with systemic lupus erythematosus had generalized lymphadenopathy and plasma cell-subtype Castleman disease.
- Both patients showed adequate response to rituximab treatment.
- The cases highlight diagnostic challenges due to overlapping clinical features.

## Abstract

Systemic lupus erythematosus is a heterogeneous autoimmune disease that commonly presents with lymphadenopathy, a feature that can lead to confusion with other diseases due to its non-specificity. Histopathological features are usually nonspecific and may mimic other conditions. Other cases have described Castleman disease, a rare lymphoproliferative disorder, in patients with systemic lupus erythematosus. This uncommon association poses diagnostic challenges due to the clinical overlap. We present cases of two Latin-American women with systemic lupus erythematosus and generalized lymphadenopathy, with histopathological findings compatible with plasma cell-subtype Castleman disease, who showed adequate response to rituximab treatment.