Predictors of renal function deterioration at one year after off-clamp non-renorrhaphy partial nephrectomy.

BACKGROUND: Preservation of renal function is an important goal in renal cell carcinoma-related surgery. Although several case-dependent techniques for renal pedicle clamping and hemostasis have been used, their effects on long-term renal function are controversial. METHODS: The clinical records of 114 patients who underwent off-clamp non-renorrhaphy open partial nephrectomy at our hospital were retrospectively reviewed. Perioperative estimated glomerular filtration rate (eGFR) preservation was calculated, and predictors of eGFR decline 12 months post-surgery and overtime deterioration of renal function were identified using a multivariate regression analysis. RESULTS: The median patient age was 65 years, and the median tumor size was 27 mm. The mean eGFR preservation at 1, 3, and 12 months post-surgery were 90.1%, 89.0%, and 86.9%, respectively. eGFR decline at 1 and 3 months were associated with poor eGFR preservation at 12 months with the odds ratio (95% confidence interval (CI)) of 1.97 and 3.157, respectively. Multivariate regression analyses revealed that tumor size was an independent predictor of eGFR decline at 12 months. Among 65 patients with eGFR preservation over 90% at 1 month post-surgery, eGFR value of 28 patients deteriorated below 90% at 12 months post-surgery compared with preoperative eGFR. Tumor size and eGFR preservation at 1 month were independent predictors of long-term renal function deterioration. CONCLUSION: Tumor size predicted eGFR decline 12 months post-surgery. Only a mild decline in eGFR was observed between 3 and 12 months after open partial nephrectomy. Tumor size and eGFR preservation at 1 month predicted the deterioration of renal function over time.

Bilateral fumarate hydratase deficient renal cell carcinoma in a patient with hereditary leiomyomatosis and renal cell cancer syndrome.

Introduction: Patients with hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome have high risks of uterine and cutaneous leiomyomas and renal cell carcinoma (RCC), which are caused by germline mutation of the fumarate hydratase (FH) gene. RCC lesions are mostly high-grade tumors with a poor prognosis. Case presentation: A 37-year-old man who had previously undergone treatment for a left RCC was referred to our hospital with a diagnosis of right RCC. Robot-assisted partial nephrectomy was performed, and the pathological diagnosis revealed fumarate hydratase (FH)-deficient RCC. The left RCC, which was originally diagnosed as mucinous tubular and spindle cell carcinoma, was reviewed and diagnosed as FH-deficient RCC. The patient's father and uncle both died of RCC, and the father's tumor was also immunohistochemically proven to be FH-deficient RCC. Conclusion: HLRCC-related RCC should be considered in a differential diagnosis of young patients with a family history of RCC.

A case of condyloma acuminatum of the bladder concurrently diagnosed with urothelial carcinoma.

Introduction: Condyloma acuminatum usually occurs in the external genitalia and rarely in the bladder mucosa. Here, we report a case of condyloma acuminatum of the bladder that was detected concurrently with urothelial carcinoma. Case presentation: A 42-year-old man was referred to our urology department with positive urine cytology for urothelial carcinoma. Cystoscopy revealed a broad-base nonpapillary bladder tumor. The patient underwent a transurethral resection of the bladder tumor. Pathological examination revealed urothelial carcinoma, high-grade pT1, and concurrent resection of condyloma acuminatum. DNA was extracted from the paraffin-embedded transurethral resection of the bladder tumor tissue specimens. HPV11 was detected in condylomas by PCR and in situ hybridization, whereas HPV was not detected in urothelial carcinomas. Conclusion: We report a rare case of condyloma acuminatum of the bladder that was concurrently diagnosed with urothelial carcinoma from the same site.

Broad subcutaneous emphysema with airway obstruction during robot-assisted partial nephrectomy: A case report and literature review.

Introduction: Subcutaneous emphysema is a relatively common complication in laparoscopic surgery. However, airway obstruction secondary to subcutaneous emphysema is rare. Case presentation: A 63-year-old woman with a 56-mm left renal tumor underwent a robot-assisted partial nephrectomy. The operative time was 155 min, the insufflation time was 108 min, and the estimated blood loss was 70 mL. The pneumoperitoneum pressure was maintained at 12 mmHg, except at 15 mmHg for 19 min during tumor resection. The end-tidal CO2 was <47 mmHg throughout the procedure. Postoperatively, broad subcutaneous emphysema from the thigh to the eyelid was observed. Computed tomography revealed airway obstruction, and extubation was aborted. On postoperative day 1, emphysema around the trachea and neck improved and the intubation tube was successfully removed. Conclusion: Both laryngeal emphysema and physical compression secondary to emphysema can cause airway obstruction. To reduce gas-related complications, the risk of developing subcutaneous emphysema should be properly assessed during robot-assisted laparoscopic surgery.

Asymptomatic renal granuloma diagnosed 3 years after Bacillus Calmette-Guérin intravesical injection: A case report and a literature review.

Introduction: Intravesical Bacillus Calmette-Guérin immunotherapy is an effective treatment for non-muscle-invasive bladder cancer, which is occasionally associated with side effects and complications. The incidence of significant renal complications after intravesical Bacillus Calmette-Guérin immunotherapy is less than 2%. We report a case of renal granuloma after intravesical Bacillus Calmette-Guérin immunotherapy for bladder cancer, which radiologically resembled a papillary renal cell carcinoma. Case presentation: A 65-year-old man, who had a medical history of urothelial carcinoma and received intravesical Bacillus Calmette-Guérin therapy, was referred to our Urology Department with a right renal tumor. Imaging findings suggested papillary renal cell carcinoma. Robot-assisted partial nephrectomy was performed, and the histopathological examination revealed epithelioid cell granuloma, which were considered to be Bacillus Calmette-Guérin-related renal granuloma. Conclusion: Bacillus Calmette-Guérin-related renal granuloma mimicking papillary renal cell carcinoma have been reported. We should consider the possibility of renal granulomas when encountering image abnormalities for patients treated with intravesical Bacillus Calmette-Guérin therapy.

Advantages of enhanced recovery after surgery program in robot-assisted radical cystectomy.

Radical cystectomy is a gold-standard treatment for muscle-invasive bladder cancer. We recently introduced robot-assisted radical cystectomy (RARC) with perioperative enhanced recovery after surgery (ERAS). The medical records of patients with bladder cancer who underwent open radical cystectomy (ORC) or RARC/ERAS at NTT Medical Center Tokyo were retrospectively reviewed to compare the surgical outcomes, hospital stay, and medical costs between groups. Multidisciplinary full ERAS items were provided for the RARC/ERAS group. The median estimated blood losses in the ORC and RARC/ERAS groups were 650 and 100 mL, and the median operative times were 312 and 445 min, respectively. In addition, the median times to liquid food intake in these groups were 6 and 0 days, the median times to first flatus and first defecation were 2 and 1 day, and 3 and 1.5 days, respectively. The rates of postoperative ileus in the ORC and RARC/ERAS groups were 27.5% and 4.5%, and the median postoperative hospital stays was 26.5 and 12 days, respectively. Medical costs excluding surgery were significantly lower in the RARC/ERAS group. In conclusion, RARC/ERAS represents a safe treatment option for muscle-invasive bladder cancer with decreased perioperative complications and lower medical costs.

Predictive factors for postoperative renal function after off-clamp, non-renorrhaphy partial nephrectomy.

Background: There is limited information on perioperative renal function during off-clamp, non-renorrhaphy open partial nephrectomy. Therefore, this retrospective study aimed to identify predictive factors of perioperative decline in renal function after off-clamp, non-renorrhaphy open partial nephrectomy. Methods: Clinical records of 138 patients with renal tumors who underwent off-clamp, non-renorrhaphy open partial nephrectomy at our institution were reviewed. Off-clamp, non-renorrhaphy partial nephrectomy was performed using a soft coagulation system. Perioperative estimated glomerular filtration rate (eGFR) preservation was calculated, and predictors were identified using multivariate regression analysis at 5 days, 1 month, and 3 months after surgery. Results: The median operation time was 122 minutes, and the median volume of estimated blood loss was 155 mL. The mean eGFR preservation at 5 days, 1 month, and 3 months after surgery was 95.3%, 91.0%, and 90.7%, respectively. Estimated blood loss was an independent predictor of perioperative decline in eGFR 5 days after surgery [odds ratio (OR): 0.97; 95% confidence interval (CI): 0.96, 0.98; P<0.001]. Preoperative eGFR and estimated blood loss were independent predictors of perioperative decline in eGFR 1 month after surgery (OR: 0.86; 95% CI: 0.77, 0.95; P=0.007 and OR: 0.98; 95% CI: 0.97, 0.99; P<0.001, respectively). Age, preoperative eGFR, and estimated blood loss were independent predictors of perioperative decline in eGFR 3 months after surgery (OR: 0.64; 95% CI: 0.54, 0.81; P<0.001, OR: 0.72; 95% CI: 0.61, 0.85; P<0.001; and OR: 0.98; 95% CI: 0.97, 0.99; P=0.004, respectively). Conclusions: Estimated blood loss during surgery was a predictor of perioperative decline in eGFR within 3 months after off-clamp, non-renorrhaphy open partial nephrectomy. Age was a predictor of perioperative decline in eGFR 3 months after surgery.

Two independent modes of kidney stone suppression achieved by AIM/CD5L and KIM-1.

The prevalence of kidney stones is increasing and its recurrence rate within the first 5 years is over 50%. No treatments that prevent the occurrence/recurrence of stones have reached the clinic. Here, we show that AIM (also called CD5L) suppresses stone development and improves stone-associated physical damages. The N-terminal domain of AIM associates with calcium oxalate crystals via charge-based interaction to impede the development of stones, whereas the 2nd and C-terminal domains capture the inflammatory DAMPs to promote their phagocytic removal. Accordingly, when stones were induced by glyoxylate in mice, recombinant AIM (rAIM) injection dramatically reduced stone development. Expression of injury molecules and inflammatory cytokines in the kidney and overall renal dysfunction were abrogated by rAIM. Among various negatively charged substances, rAIM was most effective in stone prevention due to its high binding affinity to crystals. Furthermore, only AIM was effective in improving the physical complaints including bodyweight-loss through its DAMPs removal effect. We also found that tubular KIM-1 may remove developed stones. Our results could be the basis for the development of a comprehensive therapy against kidney stone disease.

Immune-related dermatitis during combined treatment with pembrolizumab and axitinib in a patient with metastatic renal cell\x92carcinoma with stasis dermatitis.

INTRODUCTION: The combination of pembrolizumab and axitinib has recently been approved as a first-line treatment for previously untreated metastatic renal cell carcinoma. However, immune-related adverse events are not well known. CASE PRESENTATION: A 65-year-old male was diagnosed with renal cell carcinoma with metastases to the brain and lungs. The patient had a medical history of stasis dermatitis. During the combined treatment of pembrolizumab and axitinib, blisters appeared on the lower extremities. Skin biopsy revealed septal panniculitis, pustules, and perivascular lymphocytic and neutrophilic infiltration of the skin, and the patient was diagnosed with immune-related dermatitis. The dermatitis improved with oral prednisolone treatment. CONCLUSION: A case of immune-related dermatitis during combinatorial treatment with pembrolizumab and axitinib for renal cell carcinoma has been reported. Preexisting stasis dermatitis may have affected the onset and deterioration of immune-related dermatitis.

Granulomatous prostatitis with high suspicion of prostatic adenocarcinoma on radiological imaging.

INTRODUCTION: Granulomatous prostatitis is a benign inflammatory condition of the prostate that may mimic prostatic adenocarcinoma on magnetic resonance imaging findings. Even in the era of multiparametric magnetic resonance imaging, the differential diagnosis of granulomatous prostatitis from malignancy remains difficult. CASE PRESENTATION: A 69-year-old man with abnormal magnetic resonance imaging and positron emission tomography/magnetic resonance imaging findings, and a prostate-specific antigen value of 2.48 ng/mL underwent prostate needle biopsy. He had a history of urinary tract infection 3 months prior to presentation. Multiparametric magnetic resonance imaging showed low-intensity signals on T2-weighted images, slightly high-intensity signals on diffusion-weighted images, and low values on apparent diffusion coefficients. The prostate imaging-reporting and data system version 2 score was 3. Histological examination revealed granulomatous prostatitis. CONCLUSION: For patients with preceding urinary tract infections, granulomatous prostatitis should be considered as a differential diagnosis, even when magnetic resonance imaging and positron emission tomography suggest prostatic adenocarcinoma.

Assessment of surgical outcomes of off-clamp open partial nephrectomy without renorrhaphy for ≥T1b renal tumours.

PURPOSE: To assess the surgical outcomes of off-clamp open partial nephrectomy without renorrhaphy. In the era of robot-assisted surgeries, open partial nephrectomy remains a surgical option for ≥ T1b renal tumours. Although the necessity of renal pedicle clamping and renorrhaphy in open partial nephrectomy for larger tumours remains to be discussed, reports on this issue are rare. METHODS: Twenty-seven open partial nephrectomies for ≥ T1b renal tumours were performed without renal pedicle clamping or renorrhaphy. A soft coagulation system was used to control bleeding from the resection bed. Surgical results, complications, and predictors of perioperative estimated glomerular filtration rate (eGFR) preservation at 1 month and 3 months after surgery were analysed. RESULTS: The median estimated volume of blood loss was 420 mL. The rates of perioperative eGFR preservation were 88.9 and 87.3% at 1 and 3 months after surgery, respectively. Tumour size was an independent predictor of perioperative eGFR preservation at 1 month after surgery, whereas age and exophytic/endophytic properties of the tumour were independent predictors of perioperative eGFR preservation at 3 months after surgery. CONCLUSION: Open partial nephrectomy without renal pedicle clamping or renorrhaphy could be safely performed for ≥ T1b renal tumours, even when tumours were entirely endophytic and located close to the renal pedicle. Mild perioperative eGFR reduction was observed. Although surgical indications should be carefully considered in these cases, off-clamp open partial nephrectomy without renorrhaphy is a feasible procedure for patients with ≥ T1b renal tumours.

Endovascular catheter arterial embolization effectively treats secondary hypertension and increased plasma B-type natriuretic peptide level accompanied by idiopathic renal arteriovenous fistula.

A 65-year-old woman with a history of hypertension and atrial fibrillation was referred to our hospital following detection of microscopic hematuria. Physical examination showed continuous vascular murmur with the maximum point on the right side of the umbilicus. Contrast-enhanced computed tomography showed a right renal aneurysmal-type arteriovenous fistula. She underwent endovascular catheter arterial embolization. Following this, her blood pressure was virtually normalized, and her levels of plasma BNP were significantly reduced. We recommend that patients with microscopic hematuria should be auscultated around the navel, because renal AV shunt is treatable; this may facilitate cure of secondary hypertension and cardiac load.

[A CASE REPORT OF Xp11.2 TRANSLOCATION RENAL CELL CARTINOMA SUSPECTED RENAL PELVIC CARCINOMA].

The patient was a 33-year-old female who visited the Department of Gastroenterology of this hospital after experiencing lower abdominal pain and nausea. The patient was referred to this department after suspicions of right kidney hemorrhage revealed by non-contrast computed tomography (CT). We also identified hematuria macroscopically, and contrast-enhanced CT scans revealed uneven deep staining in the upper right kidney during the early phase. Furthermore, by the late phase, we identified a 29-mm solid tumor with no staining. There was no clear pseudomembrane and no clear boundary with the kidney parenchyma. Additionally, there was no metastasis to the lymph nodes and other organs. Based on the above findings, we suspected renal parenchymal infiltration of right renal cell carcinoma (RCC) or right renal pelvic carcinoma. Since the patient was young, we considered the risk of the residual tumor and performed total nephroureterectomy and lymph node dissection with an enlarged view. The inside of the resected tumor specimen showed significant necrosis and hematoma spread, which had infiltrated the renal pelvis. Based on the characteristic histological findings and genetic results obtained using the fluorescence in situ hybridization (FISH) approach, we diagnosed the patient with Xp11.2 translocation RCC. No additional treatments were provided after surgery, and even now the patient is being followed-up through outpatient visits, but there has been no recurrence or new metastasis. There have only been a few reported cases of Xp11.2 translocation RCC; therefore, in many cases, treatments and follow-up duration according to the disease stage and disease prognosis have not been determined. In this study, we report a case of Xp11.2 translocation RCC experienced at our hospital, with additional literature considerations.

[A CASE REPORT OF PRIMARY MUCOSA ASSOCIATED LYMPHOID TISSUE LYMPHOMA OF THE PROSTATE].

The patient was a 53-year-old man who was referred to the department of urology of our hospital after screening results indicated elevated prostate-specific antigen (PSA) levels. The PSA level was 5.33 ng/ml, and rectal examination revealed that the prostate was elastic and hard with mild prostatic hyperplasia. Because magnetic resonance imaging revealed abnormal signals in the prostatic transition area, prostate cancer was suspected and the patient underwent transrectal prostate needle biopsy. The pathological diagnosis was adenocarcinoma (Gleason score 5+5 = 10). After using thoracic, abdominal, and pelvic computed tomography (CT) and bone scintigraphy to confirm that metastasis had not occurred, robot-assisted radical prostatectomy (RARP) was performed. Prostate cancer was not detected during pathologic diagnosis of the surgical specimen, and on the basis of the results of re-examination with immunostaining, a diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma was made. In addition, an upper and lower endoscopy examination, positron emission tomography (PET) -CT, and bone marrow biopsy confirmed that generalized tumor lesions and lymph node swelling were not present, and the patient was diagnosed with primary MALT lymphoma of the prostate. Currently, 12 months since surgery, the patient continues to undergo follow-up as an outpatient and no recurrence has been observed. There have been only a few reports of primary MALT lymphoma of the prostate, in English or Japanese, and herein, we present our experience with a patient for whom a definitive diagnosis was difficult, along with a review of the literature.

Patient-specific 3-dimensional Printed Kidney Designed for "4D" Surgical Navigation: A Novel Aid to Facilitate Minimally Invasive Off-clamp Partial Nephrectomy in Complex Tumor Cases.

OBJECTIVE: To report our initial experience with a novel style of 3-dimensional (3D) printed kidney, which we call "4D" surgical navigation in minimally invasive off-clamp partial nephrectomy (PN). MATERIALS AND METHODS: Ten patients with a R.E.N.A.L. nephrometry score ≥8 renal mass underwent minimally invasive off-clamp PN navigated with the aid of a patient-specific 3D printed kidney. To enhance the advantage of a 3D printed organ, we herein designed our 3D printed kidneys so that the tumor and its margin could be removed. This tumor removability allowed surgeons and patients to preoperatively visualize both the pre- and posttumor-resection kidney status, which we termed "4D" surgical navigation. Before patients consented to surgery, the surgical procedure and perioperative risks were explained to each patient using the patient-specific 3D printed kidney; subsequently, surgeons asked patients whether the 3D printed kidney model had helped them better understand their surgery than they would have without the model. RESULTS: All minimally invasive off-clamp PNs were successfully completed with acceptable perioperative outcomes and negative surgical margins. The 3D printed tumors together with their margins were nearly identical to the surgical specimens. All patients responded that their specific 3D printed kidney models had helped them understand their disease and the operations they underwent. CONCLUSION: This is the first report of a novel 3D printed organ style, which we termed "4D" surgical navigation. Use of the current 3D printed kidney models helped surgeons to perform minimally invasive off-clamp PN in complex tumor cases and also helped patients to more fully understand the operation.

[IMMERSIVE SURGICAL NAVIGATION USING SPATIAL INTERACTIVE VIRTUAL REALITY AND HOLOGRAPHIC AUGMENTED REALITY].

This paper describes the potential role and limitations of current three-dimensional (3D) virtual reality (VR), augmented reality (AR), and holography for image-guided surgery. We developed a new surgical spatial navigation system using VR, AR, and virtual holography. An interactive stereo display is used to view the interactions between the surgeon and stereo images of the patient's anatomy depicted on the display by tracking the surgeon's head and hand/arm positions. Sensing the surgeon's head position creates motion parallax information, an immersive depth cue that can be added to the binocular parallax already present in the display. The beneficial applications of VR/AR devices (head-mounted devices, 3D tablets, and motion sensors) are also discussed. They allow the user to manipulate the spatial attributes of VR, which can enhance spatial reasoning and AR.

[Organ-sparing surgery for contralateral testicular tumor following orchiectomy : a case report].

A 30-year-old man underwent a left high orchiectomy because of stage I testicular tumor in December, 2006. A palpable nodule was noticed in the contralateral testicle in March, 2008. No tumor marker was elevated. Imaging studies including ultrasonography and magnetic resonance imaging showed a 13 mm tumor consisting of both a solid portion and a hemorrhagic cyst. A malignant tumor could not be ruled out completely based on examinations and his medical history. Tumor resection with partial orchiectomy was planned after informed consent. Preoperative serum concentration of free testosterone was 8.4 pg/ml, and motile sperm were found in the semen analysis. The tumor was resected while the spermatic cord was clamped transiently. The pathological diagnosis of frozen sections confirmed no malignancy, and the final pathological result was mature teratoma, no evidence of malignancy. No androgen substitution has been required. Furthermore, a few normal motile sperm were detected in the ejaculated semen after the surgery. Organ-sparing surgery for the contralateral testicular tumor following orchiectomy, can be considered to avoid infertility and hormonal substitutions.

Anteroposterior dissection HoLEP: a modification to prevent transient stress urinary incontinence.

OBJECTIVES: The prevalence of transient stress urinary incontinence (SUI) after HoLEP has been reported to be as high as 44%. Anteroposterior dissection HoLEP was newly developed to protect the urethral sphincter and therefore lower the incidence rate of SUI. This study was conducted to determine the SUI incidence rate after anteroposterior dissection HoLEP. METHODS: Sixty-eight consecutive patients with benign prostatic hyperplasia underwent HoLEP from January to December 2008. The first 31 cases (Surgery 1) underwent HoLEP according to Gilling's method. The next 37 cases (Surgery 2) underwent anteroposterior dissection HoLEP, where adenoma was dissected antegradely. This antegrade movement of the cystoscope allows the apical gland to be removed from the sphincter without causing damage. Surgical quality indexes (hemoglobin change, operating time, resected prostate volume) between the 2 groups were compared. All patients were assessed at 2 weeks postoperatively for clinical SUI, international prostate symptom score (IPSS), quality of life (QoL), and peak flow rates (Q(max)). RESULTS: Patient characteristics and surgical quality indexes did not differ between the 2 groups. Clinical SUI was found in 25.2% of cases in the Surgery 1 group, but only 2.7% in the Surgery 2 group. IPSS, QoL and Q(max.) were significantly improved postoperatively in both groups. At 2 weeks, the QoL of the Surgery 2 group was significantly improved compared with that observed for Surgery 1 (1.5 ± 1.1 vs 2.4 ± 1.0, P = .02). The Q(max.) of Surgery 2 was significantly higher compared with Surgery 1 (19.8 ± 8.4 vs 13.0 ± 4.7 ml/s, P = .02). CONCLUSIONS: These results indicate that our anteroposterior dissection HoLEP is a promising procedure to avoid postoperative SUI and also to substantially improve QoL.

Office-based transurethral resection of multiple bladder tumors using blue dye-mixed local anesthesia: a descriptive cohort study.

OBJECTIVE: Hospitalization and general anesthesia to perform transurethral resection of bladder tumors (BTs) may not be necessary for small recurrent BTs. We developed a new outpatient procedure. PATIENTS AND METHODS: Patients with recurrent small tumors who had previously undergone transurethral resection of BTs for low-grade, noninvasive BTs were eligible for this new procedure. Between July 2005 and 2007, 21 surgeries were performed on 11 patients. The patients' mean age was 65.6 years. The bladder was dilated with CO(2) using a 15.5F flexible cystoscope. Blue dye-mixed local anesthetic (2% xylocaine:indigo carmine 8:2) was injected into the tumor base. The tumor was resected using electric current via a hot cup. Patients went home without an indwelling catheter if there was no hematuria in the first urination after the procedure. RESULTS: Fifteen surgeries revealed one tumor, two had two tumors, two had three tumors, and two had six tumors. No complications requiring hospitalization occurred. Each resected specimen included a submucosal layer that allowed differentiation between pTa and pT1. No thermal degeneration was apparent in the resected stumps on pathological examination. Sixteen cases were urothelial carcinoma, and five cases were benign. Fifteen of the malignancies were noninvasive/low-grade tumors, but one case was microinvasive/high grade (G3pT1). During follow-up (mean, 8.8 months) recurrence in the bladder was found in 47%, but there was no orthotopic recurrence in the tumor-resected region. CONCLUSION: Our method allows safe resection of multiple recurrent BTs on an outpatient basis. This approach is a promising method for pathological diagnosis and favorable local control.

[IgG4-related idiopathic retroperitoneal fibrosis: a case report].

A 75-year-old man visited our hospital with the complaint of lumbago due to bilateral hydronephrosis. Computed tomographic (CT) scan revealed a thick and homogeneous retroperitoneal soft-tissue mass with isodensity to the muscle, which extended from around the kidneys to the bladder. His serum IgG4 level was extremely high. He also had proptosis. He was diagnosed as having retroperitoneal fibrosis due to IgG4- related sclerosing disease, and treated with glucocorticoid and azathioprine. After 2 months, partial regression of the mass was observed.