# Eosinophilic Angiocentric Fibrosis: An Uncommon Entity in the Spectrum of IgG4-related Disease

## TL;DR

This paper discusses eosinophilic angiocentric fibrosis, a rare condition in the nose and upper airways, and how to distinguish it from similar diseases.

## Contribution

The paper provides a detailed overview of EAF and its histologic mimickers to aid in accurate diagnosis.

## Key findings

- EAF is characterized by eosinophilia, lymphoplasmacytic inflammation, and perivascular fibrosis.
- Immunohistochemistry and serologic studies help confirm EAF as part of the IgG4-related disease spectrum.
- Accurate diagnosis requires distinguishing EAF from other similar inflammatory and neoplastic conditions.

## Abstract

Eosinophilic angiocentric fibrosis (EAF) is a rare, tumefactive inflammatory process of the sinonasal and upper respiratory tract and orbit. Numerous histologic mimickers of EAF occur in these locations.

A comprehensive literature review focused on EAF and its histologic mimickers was performed.

This manuscript serves as an overview of the histopathological characteristics of EAF and its histologic mimickers, including granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), sinonasal inflammatory polyps, epithelioid hemangioma, invasive fungal rhinosinusitis, Langerhans cell histiocytosis, rhinoscleroma, inflammatory myofibroblastic tumor, and fibromatosis.

A correct diagnosis of EAF can be reached by identifying the classic histopathologic features of prominent eosinophilia, lymphoplasmacytic inflammation, and concentric perivascular fibrosis. Additionally, as EAF sometimes lies on the spectrum of IgG4-related disease, immunohistochemistry and serologic studies can be used to aid in diagnosis.