# Endometrial Stromal Sarcoma–Associated Hypereosinophilia: A Case Report

## TL;DR

A rare case of high-grade endometrial stromal sarcoma causing unusual high levels of eosinophils in the blood is reported, highlighting its potential as a marker for hidden cancer.

## Contribution

First reported case linking peripheral eosinophilia to high-grade endometrial stromal sarcoma.

## Key findings

- Peripheral eosinophilia resolved after surgery but recurred with metastatic disease.
- Histopathology confirmed high-grade endometrial stromal sarcoma as the underlying cause.
- Eosinophilia may serve as a potential marker for underlying gynecologic malignancies.

## Abstract

Eosinophilia is a common systemic reaction to allergy, parasitic infection, or drug hypersensitivity. Rarely, it manifests as a paraneoplastic phenomenon, most commonly secondary to hematologic malignancies or extensive metastatic disease in solid tumors. There is scarce literature attributing peripheral eosinophilia to solid organ malignancies, especially gynecologic malignancies. We present the first reported case of peripheral eosinophilia secondary to high-grade endometrial stromal sarcoma (HGESS). A postmenopausal woman presented with weakness, urinary incontinence, and marked peripheral eosinophilia. An unremarkable infectious workup prompted further imaging, which revealed a uterine mass. She underwent total hysterectomy with bilateral salpingo-oophorectomy, after which her eosinophilia resolved. Histopathology confirmed HGESS. One month later, the patient re-presented with recurrent eosinophilia and was found to have new metastatic lesions on CT abdomen/pelvis. She elected to pursue hospice care. This case highlights a rare and atypical presentation of an aggressive uterine malignancy underscoring peripheral eosinophilia as a potential marker of underlying malignancy.