Study Type – Prognosis (cohort) Level of Evidence 4 What’s known on the subject? and What does the study add? Several small series studies have looked at the natural history of asymptomatic renal stones. The number of subjects in these studies ranged from 24 to 300 and duration of follow‐up ranged from 19.4 to 52.3 months. The reported incidences of spontaneous passage, progression and intervention were 3 to 15%, 33 to 77% and 7 to 26%. This study reports on the natural history of asymptomatic stones with an average size of 5.7 mm which were smaller in size than those reviewed in other series. The findings were that the incidence of spontaneous passage was higher than in other series at 20% and that the incidence of intervention was low at 7.1%. This study found that stones that were less than 5 mm in diameter were significantly more likely to pass spontaneously than stones that were larger and there were no other significant differences in the outcomes when stratified according to the initial size and location of stones. OBJECTIVE • To evaluate the long‐term outcomes of patients undergoing observation of asymptomatic renal calculi. PATIENTS AND METHODS • This is a retrospective review of 50 patients with 85 stones undergoing observation with annual imaging from January 2005 to December 2009. • The incidences of spontaneous stone passage, stone progression and intervention were evaluated and assessed for statistical difference according to initial size and location of stone. • Percutaneous nephrolithotomy, shock wave lithotripsy and ureteroscopy were performed when patients developed complications from the stones. RESULTS • Patients were followed up for a mean of 46 months. Sixteen percent had bilateral stones and 38% had multiple stones. • The average stone size was 5.7 mm and 31%, 26% and 43% of the stones were located in the upper, middle and lower pole respectively. • Overall incidences of spontaneous passage, progression and intervention were 20%, 45.9% and 7.1% respectively. • Stones measuring 5 mm or less were significantly more likely to pass (P= 0.006). • There was no significant difference in the incidence of passage according to the initial location of the stone (P= 0.092). There was no significant difference in intervention or progression according to the initial size (P= 0.477 and 0.282 respectively) or location of stone (P= 0.068 and 0.787 respectively). CONCLUSIONS • Patients with asymptomatic renal stones may be managed conservatively in view of low risk of intervention (7.1%). • Annual imaging should be performed as half of these stones will progress in size.

We describe three cases of inadvertent placement of the urinary catheter into the ureter. An 85-year-old gentleman on long-term indwelling catheter (IDC) for neurogenic bladder presented with fever and right flank pain. CT of abdomen and pelvis demonstrated the tip of the IDC to be located within the right vesicoureteric junction with acute right hydronephrosis and acute pyelonephritis. A 74-year-old woman, on long-term IDC for neurogenic bladder was found to have hydronephrosis on ultrasound imaging. Contrast-enhanced CT intravenous pyelography done subsequently showed the IDC was in the right distal ureter. A 47-year-old lady, on IDC for urinary retention and voiding dysfunction likely secondary to schizophrenia and anti-psychotic medications, presented with raised creatinine. A non-enhanced CT of her abdomen and pelvis was done and showed that the tip of the urethral IDC was located up to the left vesicoureteric junction. In all patients, the hydronephrosis resolved after changing the catheter and they were well on discharge. We also review the literature to identify the incidence, outcomes and possible risk factors. To our knowledge, only 20 cases have been reported thus far in the English literature. Although serious complications can occur, the incidence is very low. One risk factor that has been identified is long-term catheterization in patients with neurogenic bladder. We do not recommend routine imaging after catheterization in this group of patients. However, we should still be mindful of the possibility of this occurrence and evaluate and treat as necessary when clinical suspicion arises.

Despite the high prevalence of UI, only about 41% of UI sufferers had sought medical attention before. Common barriers included embarrassment, fear of surgery and misconceptions. This study emphasizes the need for policy development for UI prevention and management in Singapore.

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Penile metastasis from prostate adenocarcinoma is rare and the disease is usually disseminated at presentation. We present a case of an 83-year-old man with solitary metastasis to the penis from prostate adenocarcinoma. The clinical presentation and imaging features of penile metastasis from prostate cancer and the other primary penile tumors are discussed.