# Generalized Eruptive Histiocytosis: A Case Report in an Elderly Person With a Positive Rheumatoid Factor

## TL;DR

This case report describes a rare skin condition called generalized eruptive histiocytosis in an elderly woman, highlighting its benign nature and the need for careful monitoring.

## Contribution

The report presents a unique case of GEH with specific histopathological findings and emphasizes the importance of follow-up.

## Key findings

- The patient showed a papular eruption on the hands and forearms with histiocytic lesions positive for S100, CD45, and CD163.
- The condition spontaneously regressed, supporting its generally benign nature.
- Follow-up is crucial to monitor for progression to more aggressive histiocytosis.

## Abstract

We report a case of generalized eruptive histiocytosis (GEH) in a 63-year-old woman with unique clinical and histopathological characteristics. She presented with a papular eruption, mainly on the dorsa of the hands and forearms. Histopathology showed a nodular dermal histiocytic lesion positive for S100, CD45, and CD163 staining in larger histiocytes. EMA, CAM 5.2, and AE1/AE3 stains were negative. We discuss the differential diagnoses and stress that GEH is usually benign, with, in this case, spontaneous regression. However, cases should be evaluated carefully for the possibility of underlying disease, and follow-up is mandatory to evaluate their evolution into other types of more aggressive histiocytosis.