Can your hunch get this punch?

A 34 year-old Hispanic female with a history of nephrolithiasis presented with right flank pain and fever. A noncontrast computer tomography (CT) showed a 4.1 × 3.9 cm cystic lesion in the right kidney lower pole and a 6 mm non-obstructive renal calculus. She was treated with cephalexin for Escherichia coli (E. coli) urinary tract infection. One year later she returned to the emergency room with recurrent flank pain, fever, positive right renal punch and a bulge on her right flank (Figure 1 white arrow). A new contrast CT of the abdomen showed several fluid collections (Figure 2 black arrow) with septations located in the right kidney forming a ‘bear paw sign’ (Figure 2 white arrow inset). The largest collection (6.7 × 8.6 cm) had a sinus tract to the posterior lateral abdominal wall. The collections were drained by interventional radiology and grew Lactobacillus species. She subsequently underwent a right total nephrectomy. Pathology of the kidney showed a small tan-yellow, well circumscribed, pseudo-encapsulated, nodular mass