# Reflectance Confocal Microscopy Can Help Differentiate Adult Xanthogranulomatous Disease from Xanthelasma—A Case Report

## TL;DR

This case report shows how reflectance confocal microscopy can help distinguish a rare skin condition from a common one, improving non-invasive diagnosis.

## Contribution

Demonstrates the novel use of RCM for differentiating AXD from XP in a clinically challenging periocular area.

## Key findings

- RCM identified Touton giant cells and foamy histiocytes specific to xanthogranuloma.
- Combined RCM and LC-OCT monitoring improved postoperative follow-up.
- Histopathology confirmed RCM's diagnostic accuracy in this case.

## Abstract

Background: Adult xanthogranulomatous disease (AXD) is a rare histiocytic disorder with systemic potential, while xanthelasma palpebrarum (XP) is a common xanthoma often linked to lipid disorders. Differentiating these conditions is challenging due to overlapping features. Reflectance confocal microscopy (RCM), a non-invasive imaging tool, offers high-resolution visualization of skin structures and may aid diagnosis. Methods: We present a 71-year-old woman with periocular lesions. RCM was used to evaluate the lesions, identifying cellular and structural features. The findings were confirmed through histopathology, followed by surgical excision. Postoperative monitoring utilized RCM and LC-OCT. Results: RCM identified Touton giant cells, foamy histiocytes, and fibrosis, helping to distinguish xanthogranuloma from xanthelasma. Histopathology confirmed the diagnosis, and the patient underwent successful lesion excision without complications. Conclusions: This case underscores RCM’s utility as a diagnostic adjunct for differentiating AXD from XP in sensitive regions like the periocular area. The combined use of RCM and LC-OCT enhances monitoring for recurrence. While histopathology remains the diagnostic gold standard, RCM shows promise as a non-invasive tool, warranting further research to validate its role and develop standardized clinical protocols.