# STAT3‐Mutated Hyper‐IgE Syndrome With Retroperitoneal Abscess in Adolescence

## TL;DR

A rare case of a genetic immune disorder in an adult woman is highlighted, emphasizing the importance of diagnosing it even when unusual infections occur.

## Contribution

This case report highlights a rare presentation of HIES with a retroperitoneal abscess in adolescence, confirmed by STAT3 mutation.

## Key findings

- A heterozygous STAT3 variant (c.1145G>A, p.Arg382Gln) was identified, confirming autosomal-dominant HIES.
- The patient presented with a retroperitoneal abscess caused by methicillin-sensitive Staphylococcus aureus.
- The NIH-HIES score was 60 points, supporting the clinical diagnosis of HIES.

## Abstract

Hyperimmunoglobulin E syndrome (HIES) is a rare primary immunodeficiency disorder characterized by eczema, recurrent staphylococcal infections, and significantly elevated serum IgE levels. An 18‐year‐old female presented with acute abdominal pain and was diagnosed with a retroperitoneal abscess. She had a history of recurrent skin abscesses, otitis media, and eczema since infancy, skeletal fractures, and retained primary teeth. Laboratory findings showed a serum IgE level above 20,150 U/L and a CRP of 180.30 mg/L. Methicillin‐sensitive
Staphylococcus aureus
was cultured from the abscess drainage. The NIH‐HIES score was 60 points. Genetic testing identified a heterozygous STAT3 variant (NM_139276.3: c.1145G>A, p.(Arg382Gln)), confirming autosomal‐dominant HIES. This rare clinical presentation emphasizes the importance of considering HIES, even when deep‐seated infections develop outside typical cutaneous or pulmonary sites.

Clinicians should recognize that HIES can remain undiagnosed until adulthood. Identifying key features such as recurrent Staphylococcus aureus infections, eczema, markedly elevated IgE levels, and skeletal or dental anomalies is crucial for timely diagnosis and effective treatment, even in rare cases such as deep‐seated retroperitoneal abscesses.