A 69-year-old male presented to the emergency department with periumbilical pain radiating across his abdomen, with associated nausea and emesis. CT abdomen and pelvis with intravenous and oral contrast revealed an obstructing 5 mm ureteral calculus in the right ureterovesical junction causing severe hydroureteronephrosis of the right portion of the patient’s horseshoe kidney, a delayed right nephrogram, and severe right perinephric stranding. Additionally, there was a 1.3 cm ureteral calculus in the left ureterovesical junction, causing moderate hydroureteronephrosis of the left portion of the horseshoe kidney and mild perinephric stranding. There were also bilateral non-obstructing renal calculi in the horseshoe kidney (Figure ).\nWhile the ureteral and renal calculi accounted for the patient’s presenting symptoms of abdominal pain, the CT scan also revealed the horseshoe kidney having an associated anomalous IVC. The IVC had a “circumrenal” course surrounding the horseshoe kidney. The IVC split above the horseshoe kidney at the level of the L1 vertebral body into a pre-isthmic IVC (anterior to the horseshoe kidney) and a posterior IVC (Figure ). Below the kidney, the IVC rejoined at the level of the L5 vertebral body. On sagittal CT imaging, the IVC closely approximates the anterior and posterior aspects of the horseshoe kidney (Figure ). The right gonadal vein was noted to drain into the pre-isthmic IVC. Additionally, the right ureter took a retrocaval course posterior to the pre-isthmic IVC. There was narrowing of the right retrocaval ureter between the horseshoe kidney and the pre-isthmic IVC (Figure ).
A 73-year-old female patient with no relevant history, upper and lower endoscopies were performed due to dyspepsia, biopsies of an anal lesion reported a neuroendocrine carcinoma, in order to stage the malignancy, CT of the abdomen and pelvis revealed a lymphatic mass in front of the sacrum and presence of an anatomical variant of the left IVC, which continues with the azygos vein to the right of the thoracic spine. ().