Chyluria associated with radiofrequency ablation of renal cell carcinoma

Imaging of Perirenal and Intrarenal Lymphatic Vessels: Anatomy-based Approach

The lymphatic system (or lymphatics) consists of lymphoid organs and lymphatic vessels. Despite the numerous previously published studies describing conditions related to perirenal and intrarenal lymphoid organs in the radiology literature, the radiologic findings of conditions related to intrarenal and perirenal lymphatic vessels have been scarcely reported. In the renal cortex, interlobular lymphatic capillaries do not have valves; therefore, lymph can travel along the primary route toward the hilum, as well as toward the capsular lymphatic plexus. These two lymphatic pathways can be opacified by contrast medium via pyelolymphatic backflow at CT urography, which reflects urinary contrast agent leakage into perirenal lymphatic vessels via forniceal rupture. Pyelolymphatic backflow toward the renal hilum should be distinguished from urinary leakage due to urinary injury. Delayed subcapsular contrast material retention via pyelolymphatic backflow, appearing as hyperattenuating subcapsular foci on CT images, mimics other subcapsular cystic diseases. In contrast to renal parapelvic cysts originating from the renal parenchyma, renal peripelvic cysts are known to be of lymphatic origin. Congenital renal lymphangiectasia is mainly seen in children and assessed and followed up at imaging. Several lymphatic conditions, including lymphatic leakage as an early complication and acquired renal lymphangiectasia as a late complication, are sometimes identified at imaging follow-up of kidney transplant. Lymphangiographic contrast material accumulation in the renal hilar lymphatic vessels is characteristic of chylo-urinary fistula. Chyluria appears as a fat-layering fluid-fluid level in the urinary bladder or upper urinary tract. Recognition of the anatomic pathway of tumor spread via lymphatic vessels at imaging is of clinical importance for accurate management at oncologic imaging. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

CT features of feline lipiduria and renal cortical lipid deposition

OBJECTIVES

The aims of this study were to document the presence and prevalence of feline lipiduria and renal lipid deposition on CT, and to search for associations between the presence of lipiduria and sex, urinary tract abnormalities and urolithiasis.

METHODS

The CT examinations of 252 cats were reviewed for the presence of an antigravitational hypodense bubble in the urinary bladder with density values between -180 Hounsfield units (HU) and -20 HU. To identify associations between lipiduria and sex, urinary tract abnormalities and urolithiasis, Fisher's exact test was used. Renal cortical density measurement was performed in all cats. The Mann-Whitney test was performed to compare renal cortical density between lipiduric and unaffected cats.

RESULTS

A total of 27 domestic cats (10.7%) had CT evidence of lipiduria. Lipiduric cats had a significantly lower renal cortical density than unaffected cats (P <0.01). Male neutered cats had a significantly higher frequency of lipiduria and lower renal cortical density compared with female neutered cats (P <0.01). There was no significant difference between the groups regarding renal, ureteral or urethral abnormalities.

CONCLUSIONS AND RELEVANCE

Lipiduria is a common physiological phenomenon in cats that can be detected on routine CT examinations. Decreased renal cortical density is associated with lipiduria. This may aid in the diagnosis of feline lipiduria and help to differentiate its presence from other pathological depositions and excretions.

"Renal emergencies: a comprehensive pictorial review with MR imaging"

Superior soft-tissue contrast and high sensitivity of magnetic resonance imaging (MRI) for detecting and characterizing disease may provide an expanded role in acute abdominal and pelvic imaging. Although MRI has traditionally not been exploited in acute care settings, commonly used in biliary obstruction and during pregnancy, there are several conditions in which MRI can go above and beyond other modalities in diagnosis, characterization, and providing functional and prognostic information. In this manuscript, we highlight how MRI can help in further assessment and characterization of acute renal emergencies. Currently, renal emergencies are predominantly evaluated with ultrasound (US) or computed tomography (CT) scanning. US may be limited by various patient factors and technologist experience while CT imaging with intravenous contrast administration can further compromise renal function. With the advent of rapid, robust non-contrast MRI, and magnetic resonance angiography (MRA) imaging studies with short scan times, free-breathing techniques, and lack of ionization radiation, the utility of MRI for renal evaluation might be superior to CT not only in diagnosing an emergent renal process but also by providing functional and prognostic information. This review outlines the clinical manifestations and the key imaging findings for acute renal processes including acute renal infarction, hemorrhage, and renal obstruction, among other entities, to highlight the added value of MRI in evaluating the finer nuances in acute renal emergencies.

Asymptomatic chyluria presenting with fat-fluid level after renal microwave ablation

We present a case of asymptomatic chyluria in a 70-year-old man detected two years after microwave ablation of renal cell carcinoma. Chyluria is a rare complication of partial nephrectomy, but has not been previously reported after renal microwave ablation therapy. Recently, percutaneous thermal ablation techniques for T1a renal cancers are in surge due to comparable treatment efficacy, less invasive nature and lower complications. It is imperative to be aware of the post-ablation imaging findings and complications for correct diagnosis. Most patients with chyluria are clinically asymptomatic; therefore, serendipitous diagnosis on imaging detecting fat-fluid level may not be unusual.

Trans-urethral resection of bladder tumor (TURBT) and radiofrequency ablation of renal tumor: Rare etiologies of chyluria

Chyluria is a rare entity which is caused by abnormal communication between the lymphatic system and the urinary tract, which allows the passage of chyle into the urine. Whenever symptomatic, chyluria presents with lower urinary tract symptoms such as dysuria and hematuria. Multiple imaging modalities can aid in diagnosis such as lymphoscintigraphy, retrograde pyelography, CT scan of the abdomen and pelvis, and magnetic resonance imaging. Numerous etiologies are associated with chyluria among which are surgical interventions. Partial and radical nephrectomy have been reported in a number of symptomatic and asymptomatic cases, while radiofrequency ablation of renal tumors has been very rarely reported.

Herein, we report 2 cases of chyluria; one caused by trans-urethral resection of a bladder tumor and another by radiofrequency ablation of a renal oncocytoma. Fat-fluid level in the urinary bladder was seen on both precontrast and postcontrast images of CT scan of the abdomen and pelvis. Cystoscopy demonstrated no evidence of any abnormality of the urinary bladder.

Milky White Urine After Relief of Urinary Retention

BACKGROUND

Chyluria is a rare condition where chyle is excreted into the urine. Clinically, most patients manifest with intermittent passage of milky urine. Patients may also present with dysuria, urinary frequency, urgency, retention, or with the sequelae of chronic malnutrition.

CASE REPORT

We present a 55-year-old African American man who presented to the emergency department complaining of milky white urine, dysuria, decreased urine output, and suprapubic abdominal pain once a day. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Patients may present to the emergency department complaining of milk-colored urine, hematuria, urinary retention, or the sequelae of malnutrition. Initial evaluations should include laboratory investigations of common causes of chyluria and the severity of the potential malnutrition. If the patient presents with urinary retention, after relieving the obstruction in the emergency department, assessment for clot/chyle burden and likelihood of recurrence of urinary retention should be performed by urology. Arrangements for proper outpatient follow-up should be made if the disease manifestations are not severe enough to warrant admission.

CT detection of fat retention in the bladder after partial nephrectomy

PURPOSE

This study aimed to investigate the frequency of fat retention in the bladder using postoperative computed tomography (CT) and the associated imaging or clinical findings in patients who underwent renal tumor surgery.

METHODS

We retrospectively reviewed postoperative CT images from 123 patients who underwent surgery for renal tumors (92 patients after partial nephrectomy and 31 after total nephrectomy). Furthermore, we evaluated preoperative tumor characteristics per an established standardized nephrometry scoring system (the R.E.N.A.L Nephrometry Score) for patients with partial nephrectomy. We also investigated whether collecting system repair occurred during surgery.

RESULTS

Fat retention in the bladder was found in 5 patients (5.4%) after partial nephrectomy, but was not observed in any patients after total nephrectomy. No fat retention was seen immediately after partial nephrectomy (4-8 days), but occurred 2-15 months after the surgery. Subsequently, intravesical fat retention disappeared in 3 patients (8, 24, and 16 months later), and it persisted from 19-22 months after surgery in the remaining 2 patients. Collecting system repair occurred in 25 patients (27%) with partial nephrectomy. There was no statistically significant association between fat retention in the bladder and intraoperative collecting system repair (p = 0.12). The association with intravesical fat retention was not significant for either tumor size, distance to the collecting system, or the R.E.N.A.L. Nephrometry Score.

CONCLUSION

Fat retention in the bladder after partial nephrectomy can be observed using CT, although it is relatively rare. It is clinically asymptomatic and disappears spontaneously in most cases.

It is unnecessary to completely mobilize the kidney in retroperitoneoscopic renal pedicle lymphatic disconnection for intractable chyluria

PURPOSE

To compare the efficacy and safety of two approaches in retroperitoneoscopic renal pedicle lymphatic disconnection (RRPLD) for intractable chyluria: completely or partly mobilize the kidney.

MATERIALS AND METHODS

Retrospectively reviewed the clinical data of 77 patients, who underwent RRPLD because of intractable chyluria in our institution. We mobilized the whole affected kidney in 22 patients during the operation, but only dissected the lower part in other 55 patients. Operative time, blood loss, visual analog scale (VAS) score, postoperative bed rest, postoperative hospital stay, recurrence, intraoperative and postoperative complications were compared between the two groups.

RESULTS

All operation was successful, and none convert to open. The chyluria was resolved immediately after surgery. Compared with completely mobilized RRPLD (CMR), partly mobilized RRPLD (PMR) was superior in terms of operative time (132.91 ± 35.65 vs. 91.73 ± 24.14 min), blood loss (35.68 ± 8.21 vs. 25.09 ± 7.41 ml), VAS score (4.63 ± 0.44 vs. 2.34 ± 0.80), postoperative bed rest (3.36 ± 0.49 vs. 1.80 ± 0.85 days) and hospital stay (6.77 ± 1.57 vs. 4.98 ± 1.89 days). Compilations occurred in three patients in CMR group and two in PMR. Recurrence was confirmed by cystoscopy in three patients during 3-103-month follow-up, CMR group with 1 and PMR with 2.

CONCLUSION

In our study, we found PMR was equally effective and safe as CMR. Moreover, it is more minimally invasive, painless and economical. Therefore, we believe it is unnecessary to completely mobilize the kidney in RRPLD for intractable chyluria.

Lipiduria presenting following right hemicolectomy: A case presentation and brief review of the literature

Lipiduria, also known as lipuria, refers to the presence of lipids within the urine. When lipids are present in macroscopic quantities, lipiduria can be visualized as a fat-fluid level on computed tomography imaging. Although the general differential diagnosis of lipiduria is broad, reported etiologies of lipiduria diagnosed by computed tomography have primarily included chyluria, urine-induced lipolysis, and trauma. We report a case of lipiduria occurring coincidentally with resolution of perivesical fat necrosis in a patient after partial right hemicolectomy for B cell lymphoma.

Modified retroperitoneoscopic renal pedicle lymphatic disconnection for intractable chyluria

INTRODUCTION

To describe a modified retroperitoneoscopic renal pedicle lymphatic disconnection (MRRPLD) and to compare the efficacy and safety of MRRPLD with traditional retroperitoneoscopic renal pedicle lymphatic disconnection (RRPLD).

TECHNICAL CONSIDERATIONS

From September 2008 to July 2012, RRPLD and MRRPLD were performed respectively on 18 and 14 patients at our center. Comparison was conducted including operative time, intraoperative blood loss, postoperative time of bed rest, hospital stay, postoperative urine chyle test, and complications. All operations were completed without conversion to open surgery. The mean operative time, intraoperative blood loss, postoperative time of bed rest, and hospital stay from MRRPLD group were all decreased compared with data from RRPLD group. There was significant difference in operative time, postoperative time of bed rest, and hospital stay (P <.05). Complications occurred only in 1 patient receiving RRPLD. Chyluria disappeared in all patients after the operation. No recurrence was observed during the follow-up.

CONCLUSION

MRRPLD has a good effect and safety for chyluria. It is a simpler, more minimally invasive, and more economic surgical therapy compared with traditional RRPLD.

Non-tropical chyluria: CT diagnosis

Chyluria is commonly associated with filariasis, which is prevalent among the population of tropical and subtropical regions. Chyluria is seldom encountered in the United States and other western countries, but may occur if the flow of chyle into the thoracic duct is blocked due to inflammatory, neoplastic, or various other etiologies. We report 10 adult patients, in whom the detection of fat-urine level in their bladder on abdominal CT provided the initial diagnostic clue to the presence of chyluria. This series included 7 men and 3 women, who ranged in age from 25 to 91 years (mean: 62 years). The associated lesions included renal angiomyolipomas (2), lymphangiomas of the kidney and bladder (1), metastatic testicular cancer (1), postoperative status following partial nephrectomy for renal cell carcinoma (4), left radical nephrectomy (1), and segmental cystectomy for carcinomas (1). The clinical and radiological features of this entity are presented along with a brief review of the pertinent literature.

Intramural vesicular fat--an uncommon CT finding

We present a case of a 75-year-old male who presented with lower back pain found to have an incidental finding of intramural vesicular fat on an unenhanced computed tomography of the pelvis. This relatively uncommon finding of a normal entity should not be mistaken for other causes of pathology within the urinary bladder.

Chyluria after radiofrequency ablation of renal tumors

PURPOSE

To assess the incidence of chyluria after radiofrequency (RF) ablation of renal tumors and attempt to identify predictors of this phenomenon.

MATERIALS AND METHODS

Over a 3-year period, 62 consecutive patients with renal tumors were treated by percutaneous computed tomography (CT)-guided or laparoscopic RF ablation, of which 41 underwent at least three posttreatment CT studies and were evaluated in this study. Three radiologists reviewed the pretreatment and posttreatment CT images for the presence or absence of fat-fluid levels in the bladder, the location of the tumor, and the size of the postablation defect. A logistic regression model was used to assess whether ablation defect size or tumor location predicted chyluria.

RESULTS

Chyluria was detected at a mean time of 44.5 weeks in 17 (41%) of 41 patients with renal tumors treated by RF ablation. A pretreatment biopsy specimen showed renal cell carcinoma in 74%. Mean tumor size was 2.77 cm, and mean initial ablation size was 4.2 cm. Chyluria persisted in seven patients. Zone of ablation defect size and tumor location were not significant predictors of chyluria (P = .64 and P = .42). Mean follow-up was 77 weeks.

CONCLUSIONS

Chyluria is a common and asymptomatic finding in a significant proportion of patients undergoing RF ablation for renal tumors. Tumor location and zone of ablation defect size were not predictors of chyluria. The presence of a fat-fluid level should not be mistaken for an air-fluid level.