Calyceal diverticula are common incidental findings and can be demonstrated on multiple imaging modalities. Although benign and usually asymptomatic, they may mimic more significant pathology such renal tumor on cross-sectional imaging, or rib metastases on bone scan. Recognition of classical findings may help to differentiate from this more serious pathology. CT urogram or IVU is more likely to be diagnostic by demonstrating communication with the pelvicalyceal system, but ultrasound may also be diagnostic if mobile echogenic material is demonstrated.

From the manuscript

Calyceal Diverticulum - a Mimic of Different Pathologies on Multiple Imaging Modalities

Abstract
Calyceal diverticula are outpouchings of a renal calyx. Often found incidentally on radiological imaging, they are generally benign and usually asymptomatic, although complications include infection and stone formation. More importantly, calyceal diverticula may mimic other potentially more serious pathology on imaging, such as renal tumour or abscess on ultrasound or computed tomography and even rib metastasis on bone scintigraphy. We present a case of a patient with a calyceal diverticulum found incidentally on imaging, in which the diverticulum is demonstrated on ultrasound, computed tomography, intravenous urogram and bone scintigraphy, and discuss the potential differential diagnoses that need to be excluded in this condition.