Caroline C. Billingsley

Purple urine bag syndrome is a rare phenomenon whose striking presentation can lead to earlier recognition and treatment of a potentially serious medical condition. This is a unique condition of long11 term indwelling catheter associated urinary tract infection with distinct, purple-colored urine caused by bacterial metabolites. This infrequent occurrence was seen in a patient with stage IIIb squamous cervical cancer who presented to the emergency department with symptoms of a urinary tract infection in setting of indwelling bilateral percutaneous nephrostomy tubes. The patient’s physical exam was notable for left costovertebral tenderness, purple urine in bilateral nephrostomy bags and urine culture significant for proteus mirabalis. The patient was treated with intravenous antibiotics and fluid resuscitation. She unfortunately left against medical advice shortly after being admitted. She re presented to an outside hospital with fevers and non-draining nephrostomy tubes notable to have purulent discharge at the nephrostomy sites. The scant urine through the nephrostomy tubes was also noted to have a purple hue. She was found to have another urinary tract infection with Enterobacter cloacae and subsequently treated with intravenous antibiotics. During this admission, she underwent bilateral nephrostograms notable for significant clogging of tubes and bilateral ureteral patency. After the study, she underwent removal of the long-term indwelling catheters and was able to continue voiding spontaneously. She was discharged in good condition on a ten-day course of oral antibiotics. The occurrence of purple urine is highly associated with urinary tract infections. This process is thought to be caused by a metabolism of dietary tryptophan by intestinal bacteria to indole that is then absorbed into the circulation and then converted to indoxyl sulfate by hepatic enzymes. This substrate returns to circulation and is excreted in the urine where in the presence of bacteria with sulfatase and phosphatase activity converts indoxyl sulfate to indigo and indirubin resulting in the characteristic purple hue of the urine. Catheter associated urinary tract infections require antibiotic treatment and timely removal of catheter when appropriate to prevent complications including pyelonephritis and sepsis.

BACKGROUND: DNA polymerase ɛ (POLE) exonuclease domain mutations characterize a subtype of endometrial cancer (EC) with a markedly increased somatic mutational burden. POLE‐mutant tumors were described as a molecular subtype with improved progression‐free survival by The Cancer Genome Atlas. In this study, the frequency, spectrum, prognostic significance, and potential clinical application of POLE mutations were investigated in patients with endometrioid EC.METHODS: Polymerase chain reaction amplification and Sanger sequencing were used to test for POLE mutations in 544 tumors. Correlations between demographic, survival, clinicopathologic, and molecular features were investigated. Statistical tests were 2‐sided.RESULTS: Thirty POLE mutations (5.6%) were identified. Mutations were associated with younger age (P=.001). POLE mutations were detected in tumors with microsatellite stability (MSS) and microsatellite instability (MSI) at similar frequencies (5.9% and 5.2%, respectively) and were most common in tumors with MSI that lacked mutL homolog 1 (MLH1) methylation (P<.001). There was no association with progression‐free survival (hazard ratio, 0.22; P=.127).CONCLUSIONS: The discovery that mutations occur with equal frequency in MSS and MSI tumors and are most frequent in MSI tumors lacking MLH1 methylation has implications for Lynch syndrome screening and mutation testing. The current results indicate that POLE mutations are associated with somatic mutation in DNA mismatch repair genes in a subset of tumors. The absence of an association between POLE mutation and progression‐free survival indicates that POLE mutation status is unlikely to be a clinically useful prognostic marker. However, POLE testing in MSI ECs could serve as a marker of somatic disease origin. Therefore, POLE tumor testing may be a valuable exclusionary criterion for Lynch syndrome gene testing. Cancer 2015;121:386–394. © 2014 American Cancer Society.