# Brainstem Encephalitis in Neuropsychiatric Systemic Lupus Erythematosus Mimicking Malignant Lymphoma: A Case Report and Literature Review

## TL;DR

A rare case of brainstem encephalitis caused by lupus was mistaken for cancer, but treatment with immunosuppressants improved the patient's condition.

## Contribution

This case highlights the diagnostic challenge of differentiating NPSLE from lymphoma and emphasizes the need for early biopsy and treatment.

## Key findings

- The patient showed brainstem lesions and lymphadenopathy, mimicking malignant lymphoma.
- Histopathology confirmed the absence of malignancy, and immunosuppressive therapy led to neurological improvement.

## Abstract

We report a rare case of neuropsychiatric (NP) systemic lupus erythematosus (NPSLE) manifesting as brainstem encephalitis with generalized lymphadenopathy. A 32-year-old woman developed altered consciousness, fever, and pancytopenia, with diffusion-restricted brainstem lesions and elevated soluble interleukin-2 receptor (sIL-2R) levels in both serum and cerebrospinal fluid (CSF), accompanied by systemic lymphadenopathy and cytopenia, strongly mimicking malignant lymphoma. Histopathology excluded malignancy. The patient underwent immunosuppressive therapy with corticosteroids and cyclophosphamide, leading to marked neurological improvement. This case highlights the diagnostic challenge in differentiating NPSLE with brainstem involvement from lymphoproliferative disorders and underscores the importance of early biopsy and prompt immunosuppressive intervention to achieve favorable outcomes.