# The Great Vasculitis Pretenders: Mycotic Pseudoaneurysm, Aortitis with Occlusive Iliac Thrombus, and Paraneoplastic Aortitis. A Case-Based Review

## TL;DR

This paper reviews three cases where conditions mimicked vasculitis, highlighting the importance of accurate diagnosis to avoid harmful treatments and delays in care.

## Contribution

The paper presents a case-based review emphasizing the diagnostic challenges of distinguishing vasculitis from its mimickers.

## Key findings

- Mycotic pseudoaneurysm and infectious occlusive iliac thrombus were misdiagnosed as vasculitis in immunosuppressed patients.
- Paraneoplastic aortitis was associated with malignancy and Crohn-related fistulas, leading to poor outcomes.
- Misdiagnosis of vasculitis can result in unnecessary treatments and delayed surgical interventions.

## Abstract

Vasculitides encompass a group of inflammatory diseases that affect blood vessels, leading to vessel wall thickening, ischemia, and potential organ damage. While rare, the prevalence of vasculitis has increased in recent years. Its presentation often mimics infectious and paraneoplastic diseases, requiring the identification of risk factors and individualised diagnostic workup. Delayed or inaccurate diagnosis of vasculitis can result in significant morbidity, vascular complications, and death since specific therapy depends on underlying aetiology and pathology. This case series highlights three patients presenting with mycotic pseudoaneurysm, infectious occlusive iliac thrombus relative to a chronic state of immunosuppression, infections, and malignancy associated with Crohn-related fistulas, Campylobacter fetus bacteraemia, and paraneoplastic aetiologies, resulting in poor patient outcomes. It is crucial to distinguish primary vasculitis from secondary aetiologies and mimickers, as misdiagnosis can lead to unnecessary, potentially harmful treatments and delay in surgical interventions if indicated.