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

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.