# Systemic Sarcoidosis With Neurosarcoidosis Features as a Risk Factor for Multifocal Osteonecrosis

## TL;DR

This paper reports a rare case of multifocal osteonecrosis in a patient with systemic sarcoidosis, highlighting a potential link between the two conditions.

## Contribution

The paper presents the first documented case of multifocal osteonecrosis in the context of systemic sarcoidosis.

## Key findings

- A patient with systemic sarcoidosis developed multifocal osteonecrosis despite limited corticosteroid use.
- Neuropsychiatric manifestations of sarcoidosis may contribute to the development of multifocal osteonecrosis.
- The case suggests a need for further research into the pathogenesis of multifocal osteonecrosis in sarcoidosis.

## Abstract

Sarcoidosis is a systemic inflammatory disease that affects diverse organs such as the lungs, skin, eyes, and brain. Osseous involvement in sarcoidosis usually affects bones of the appendages with direct infiltration of non-caseating granulomas without bony infarcts. Symptoms of sarcoid bone lesions respond well to corticosteroid therapy. In contrast, corticosteroids act as a risk factor for the development of osteonecrosis resulting in pain and disability. Osteonecrosis that involves three or more different anatomic sites, defined as multifocal osteonecrosis (MFON), is rare. MFON has not been documented in the setting of sarcoidosis. We report a systemic sarcoidosis patient with predominant neuropsychiatric manifestations, who progressively developed MFON. Despite the limited use of corticosteroid treatment, the high burden of systemic sarcoidosis and its related neuropsychiatric involvementmay have collectively contributed to the development of MFON. This case highlights the rare association of MFON with systemic sarcoidosis and the need for further investigation into the underlying pathogenesis of MFON to prevent disability and morbidity.