Urachal abscess mimicking malignant tumor: can imaging tell them apart?

The urachus is an embryonic remnant that usually involutes before birth. Abnormal persistence of this structure can lead to infectious or neoplastic complications later in life. We report a case of an 84-year-old man that presented with a urachal complex mass which, after proper investigation, revealed to be a urachal abscess. Urachal abscesses are rare and usually occur in severe infections. Urachal abscesses can be indistinguishable from urachus carcinoma on imaging studies. This article reviews the clinical and imaging aspects of urachal abscess and carcinoma and possible differentiating elements in imaging. However, definitive diagnosis usually depends on a biopsy or fluid aspiration.