Psoas mass index at the level of the third lumbar vertebra on computed tomography is a prognostic predictor for metastatic castration-sensitive prostate cancer.

BACKGROUND: Computed tomography-defined low skeletal muscle mass is associated with oncological outcomes in patients with prostate cancer. However, its association with the outcomes of hormone-treated metastatic castration-sensitive prostate cancer remains unclear. We aimed to determine the association between metastatic castration-sensitive prostate cancer and psoas muscle parameters. METHODS: We retrospectively reviewed 121 patients with N1 and/or M1 metastatic castration-sensitive prostate cancer who underwent primary androgen deprivation therapy between 2005 and 2021, either by administration of luteinizing hormone-releasing hormone agonist/antagonist or by surgical castration accompanied by bicalutamide, a first-generation antiandrogen. Before treatment administration, the psoas muscle index at the level of the third lumbar vertebra (psoas muscle area [cm2]/height2 [m2]) and the mean Hounsfield units of the psoas muscle were evaluated using non-contrast computed tomography and in relation to oncological outcomes. RESULTS: The median follow-up was 56.9 months. Furthermore, during follow-up, 82 (67.7%) and 53 (43.8%) patients progressed to castration-resistant prostate cancer and died, respectively. Multivariate analysis of castration-resistant prostate cancer-free survival and overall survival showed significant differences in the Gleason score, clinical N-stage, and psoas muscle index (median cutoff: 3.044 cm2/m2). CONCLUSIONS: Pretreatment psoas muscle index is an independent predictor of poor castration-resistant prostate cancer-free survival and overall survival in patients with N1 and/or M1 metastatic castration-sensitive prostate cancer.

[Role of Bone Scan Index (BSI) in the Prognosis and Treatment Efficacy in Castration-Sensitive Prostate Cancer Patients with Bone Metastasis].

Bone is the most common metastatic site in prostate cancer (PCa). Although the extent of disease (EOD) grade is used for evaluating burden of bone metastasis, the accuracy of bone metastasis classification needs improvement. Bone scan index (BSI) was developed as a quantitative tool to enhance the interpretability and clinical relevance of the bone scan. This study aimed to explore the role of BSI using BONENAVI® software in determining the prognosis and treatment efficacy in castration-sensitive PCa (mCSPC) patients with bone metastasis. We retrospectively reviewed 61 mCSPC patients with bone metastasis who had received primary androgen deprivation therapy (PADT) at our institution. All patients received PADT with luteinizing hormone-releasing hormone agonist or surgical castration accompanied by first-generation antiandrogen, bicalutamide. Bone scans were performed with 99[m]Tc-MDP. BSI (%) was divided into two groups (＜1.0 and ≧1.0), and BSI response rates(change at 0 months to after 6 months) were determined using thresholds of 45% decline. Castration-resistant prostate cancer (CRPC) -free survival (CRPC-FS) and Overall survival (OS) rates were analyzed using the Kaplan-Meier method. The median follow-up was 41. 9 months. Overall, 16 patients (26. 2%) died. Multivariate analysis on pretreatment factors revealed that hemoglobin (P＝0.03) and BSI (P＝0.04) were independent prognostic factors for OS. The 5-year OS rates in patients with low BSI and high BSI were 84.6% and 39.2%, respectively (P＝0.02). In 40 patients who had a bone scan before and after PADT, OS rates in patients with a good response (≧45%) were significantly higher than those with a poor response (＜45%) (P＝0.001). Nadir PSA titers within 6 months after the start of treatment (P＝0.005), Hb (P＝0.003), and BSI change (P＝0.014) were independent prognostic factors for OS. In mCSPC patients with bone metastases, BSI at diagnosis was an important predictor of CRPC progression and OS as a pre-treatment factor, and BSI change rate and PSA nadir as post-treatment factors.

Prostate fibroblasts enhance androgen receptor splice variant 7 expression in prostate cancer cells.

BACKGROUND: Androgen receptor splice variant (AR-V) expression has been associated with prostate cancer (PCa) progression to castration-resistant PCa during androgen deprivation therapy, which reduces androgen production and inhibits androgen action in PCa cells. However, the mechanisms whereby aberrant AR-V expression is increased in PCa are still largely unknown. Fibroblasts in tumor stroma influence PCa initiation and aggressiveness, and which may play a crucial role in eliciting genetic changes during malignant transformation in human prostate epithelium. Here, our aim was to determine whether prostate fibroblasts in tumor stroma induce aberrant AR-V7 expression in PCa cells under low androgen concentration. METHODS: We performed in vitro experiments using androgen-sensitive, AR-positive PCa cell lines (LNCaP and 22Rv1 cells), commercially available prostate stromal cells (PrSC), and primary cultured prostate fibroblasts (pcPrF) from PCa specimens collected from biopsies of patients with advanced PCa. PCa cells were cocultured with each of the three fibroblast lines (PrSC, pcPrF-M37, and pcPrF-M48). RESULTS: The proliferation under low androgen concentration of LNCaP and 22Rv1 cells cocultured with PrSC, pcPrF-M37, or pcPrF-M48 was significantly increased compared to that of PCa cells cultured alone. Androgen receptor-full length (AR-FL) protein expression was increased in LNCaP and 22Rv1 cells cocultured with PrSC, pcPrF-M37, or pcPrF-M48. AR-V7 protein expression was increased in 22Rv1 cells cocultured with PrSC, pcPrF-M37, or pcPrF-M48. Under low androgen concentration, AR-V7 protein expression was slightly detected in LNCaP cells cocultured with PrSC or pcPrF-M37. Cytokine array analysis revealed that monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) levels in the conditioned medium of 22Rv1 cells cocultured with PrSC, pcPrF-M37, or pcPrF-M48 were increased under low androgen concentration. High IL-8 concentration (30 ng/ml) resulted in significantly increased protein expression of AR-FL, AR-V7, and phospho-NF-κB p65 in 22Rv1 cells. In contrast, IL-8 antibody (1 µg/ml) decreased AR-V7 protein expression in 22Rv1 cells cocultured with PrSC, pcPrF-M37, or pcPrF-M48. CONCLUSIONS: pcPrF from PCa specimens increase the expression of aberrant AR-V7 in PCa cells. IL-8 may be a target for preventing the expression of aberrant AR-Vs in PCa.

Virtual crossmatching and epitope analysis in kidney transplantation: What the physician involved in kidney transplantation should know?

Solid-phase single antigen bead (SAB) assay for detection of anti-human leukocyte antigen (HLA) antibodies and high-resolution HLA typing have enabled tremendous progress in virtual crossmatch (VXM) technology in recent years. However, misinterpretation of the SAB assay may result in detrimental consequences after kidney transplantation. Meanwhile, epitope analysis could be an effective method to estimate immunizing eplets, which may provide ancillary information for better understanding of the SAB assay. To perform epitope analysis appropriately, it is necessary to understand the basic principles related to histocompatibility testing and the characteristics of the SAB assay. Therefore, knowledge of the properties and limitations of the SAB assay is critical. In this review, we aim to describe the fundamental concepts regarding immunobiological assessment, including HLA, anti-HLA antibodies, and SAB assay, and explain epitope analysis using examples.

Real-world effectiveness of nivolumab and subsequent therapy in Japanese patients with metastatic renal cell carcinoma (POST-NIVO study): 36-month follow-up results of a clinical chart review.

OBJECTIVES: To examine the long-term effectiveness of nivolumab monotherapy and following subsequent therapies for metastatic renal cell carcinoma (mRCC) in Japanese real-world settings. METHODS: This was a multicenter, retrospective, observational study, with a 36-month follow-up, and conducted in Japanese patients with mRCC who initiated nivolumab monotherapy between 1 Feb 2017 and 31 Oct 2017. Endpoints included overall survival (OS), progression-free survival (PFS), and objective response rate (ORR). RESULTS: Of the 208 patients, 36.5% received nivolumab monotherapy as second-line, 30.8% as third-line, and 31.7% as fourth- or later-line therapy. By 36 months, 12.0% of patients continued nivolumab monotherapy; 88.0% discontinued, mainly because of disease progression (66.7%). The median (m) OS was not reached irrespective of treatment line, with a 36-month OS rate of 54.3% (second-line, 57.4%; third-line, 52.6%; fourth- or later-line, 52.9%). The ORR was 24.2% and five patients achieved complete response. The OS from first-line therapy was 8.9 years. In the 95 patients receiving therapy after nivolumab, 87.4% received vascular endothelial growth factor receptor-tyrosine kinase inhibitors, with mOS and mPFS of 27.4 and 8.1 months, respectively. Irrespective of treatment line, the mOS was not reached in patients with International Metastatic RCC Database Consortium (IMDC) favorable or intermediate risk at mRCC diagnosis. CONCLUSIONS: This 36-month real-world follow-up analysis showed a survival benefit of nivolumab monotherapy for patients with mRCC. The long-term effectiveness of sequential therapy from first-line therapy to therapy after nivolumab was also demonstrated. Additionally, nivolumab monotherapy was beneficial for patients with favorable IMDC risk at the time of mRCC diagnosis.

[Idiopathic Thrombocytopenia Purpura After Pembrolizumab Treatment Against Locally Recurrent Bladder Cancer : A Case Report].

A man in his 70s visited our hospital for gross hematuria. He was diagnosed with invasive urothelial carcinoma (cT3N2M0) and underwent total cystectomy and ileum conduit construction after three courses of neoadjuvant chemotherapy. Eight months after the operation, the disease reoccurred in the pelvic lesion. He received pembrolizumab therapy but developed idiopathic thrombocytopenic purpura (ITP) immediately before the ninth course of administration; and, treatment was discontinued. Recovery of symptoms and normalization of blood test data were achieved 3.5months after starting steroid treatment. Reduction of recurrent disease has been maintained for 2 years.

Disruption of the glomerular basement membrane associated with nutcracker syndrome and double inferior vena cava in Noonan syndrome: a case report.

BACKGROUND: Nutcracker syndrome (NCS) is characterized by compression of the left renal vein (LRV) between the aorta and the superior mesenteric artery. While rare, NCS was reported to be accompanied by double inferior vena cava (IVC). We herein report a case of Noonan syndrome (NS) with double IVC who presented with macrohematuria and proteinuria. CASE PRESENTATION: The patient was a 23-year-old man, who had been diagnosed with NS due to RIT1 mutation, after showing foamy macrohematuria 3 weeks previously. A physical examination revealed low-set ears and a webbed neck. A urinalysis showed hematuria and proteinuria, and urinary sediments showed more than 100 isomorphic red blood cells per high-power field. His proteinuria and albuminuria concentrations were 7.1 and 4.5 g/g⋅Cr, respectively. Three-dimensional contrast-enhanced computed tomography (CT) showed double IVC and narrowing of the LRV after interflow of the left IVC. The aortomesenteric angle on a sagittal reconstruction of the CT image was 14.7°. Cystoscopy revealed a flow of macrohematuria from the left ureteral opening. On Doppler ultrasonography, there was scant evidence to raise the suspicion of the nutcracker phenomenon. Since severe albuminuria continued, a left kidney biopsy was performed. Light microscopy showed red blood cells in Bowman's space and the tubular lumen. Electron microscopy revealed disruption of the glomerular basement membrane (GBM). Vulnerability of the GBM was suspected and a genetic analysis revealed a heterozygous mutation at c.4793 T > G (p.L1598R) in the COL4A3 gene. Screening for coagulation disorders revealed the factor VIII and von Willebrand factor (vWF) values were low, at 47.6 and 23%, respectively. A multimer analysis of vWF showed a normal multimer pattern and he was diagnosed with von Willebrand disease type 1. As the bleeding tendency was mild, replacement of factor VIII was not performed. His macrohematuria and proteinuria improved gradually without treatment, and his urinalysis results have been normal for more than 6 months. CONCLUSIONS: The present case showed macrohematuria and proteinuria due to NCS in NS with double IVC and von Willebrand disease type 1. The macrohematuria and proteinuria originated from glomerular hemorrhage because of vulnerability of the GBM due to COL4A3 mutation.

Impact of family history on clinicopathological variables and disease progression in Japanese prostate cancer patients undergoing robotic-assisted radical prostatectomy.

OBJECTIVE: We evaluated whether a first-degree family history (FH) of prostate cancer (PCa) in Japanese patients undergoing robotic-assisted radical prostatectomy (RP) is correlated with clinicopathological variables and disease progression. METHODS: We reviewed consecutive 392 localized PCa patients undergoing robotic-assisted RP at our institution between 2015 and 2020. Information on FH was obtained via a self-administered questionnaire. A positive FH was defined as having a first-degree FH: a father and/or one or more brothers with PCa prior to diagnosis. All patients had clinically localized PCa treated by robotic-assisted RP. We evaluated the relationship between clinical characteristics, pathological findings, and biochemical progression-free survival (bPFS) according to first-degree FH status. RESULTS: Median follow-up was 20.8 months. FH was identified in 42 (10.7%) patients. Patients in the FH group (median, 64.8 years) were diagnosed at a significantly younger age than patients in the non-FH (NFH) group (patients without FH) (median, 67.7 years) (p = 0.003). The 5-year bPFS in the FH and NFH groups was 72.0% and 78.1%, respectively (p = 0.90). A subgroup analysis revealed a significant difference in prostate-specific antigen (PSA) density between the FH group (median, 0.51 ng/ml/cm3 ) and the NFH group (median, 0.29 ng/ml/cm3 ) in patients younger than 60 years (p = 0.033). CONCLUSIONS: In this RP population, FH of PCa was not associated with worse clinical characteristics, pathological findings, or disease progression. Patients with a FH underwent surgery at a significantly younger age, and among patients <60 years, patients with a FH had significantly higher PSA density compared with patients without a FH.

[Initial Experience of Photodynamic Diagnosis-Assisted Transurethral Resection of Bladder Tumor (PDD-TURBT)].

Photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) is expected to be useful in preventing oversight of non-muscle-invasive bladder cancer (NMIBC) and in reducing the intravesical recurrence rate after transurethral resection of bladder tumor (TURBT). We report our initial experience with28 cases of PDD-assisted TURBT (122 samples) performed at our hospital from February 2018 to April 2019. The median age of the patients was 74.5 years, and 18 of the 28 were primary cases. Each patient underwent TURBT with oral administration of 5-ALA 20 mg/kg 3 hours before endoscopic examination. The sensitivity was 89.8% when both white light and blue light were used, which was superior to the sensitivity of 67.8% when using only white light (p＜0.01, McNemar's test). Among the first several cases, we experienced high false positivity, which suggested that some experience may be required to discriminate tumors from inflammatory lesions. In fact, the specificity and the positive likelihood ratio improved with experience. No grade 2 or higher adverse events were observed among our cases. The median follow-up period was 738 days, and 9 of 28 patients (32. 1%) had recurrence within the follow-up period. In conclusion, our initial experience with PDD-assisted TURBT demonstrated its excellent diagnostic sensitivity and safety, as previously reported.

[Presurgical Treatment with Axitinib and Pembrolizumab Reduced Operation Risk by Downsizing the Vena Cava Tumor Thrombus in Clear Cell Renal Cell Carcinoma : A Case Report].

A woman in her seventies complained of chest pain during exertion and visited a local hospital. Computed tomographic scan showed right renal cell carcinoma with inferior vena cava (IVC) tumor thrombus extending above the diaphragm, and the patient was referred to our hospital. She was diagnosed with right renal cell carcinoma cT3cN0M0, with level IV IVC thrombus by Mayo classification. Axitinib and pembrolizumab were administered against intractable advanced renal cell carcinoma. The dose of axitinib was reduced due to grade 3 liver dysfunction. Right nephrectomy together with IVC thrombectomy was performed because the primary lesion had shrunk, and the level of IVC thrombus had become level III. The pathological results were clear cell carcinoma, pT3c, G3, Fuhrman grade3, INFA, v1, and ly0. Axitinib and pembrolizumab might be a presurgical option against an intractable renal cell carcinoma with an IVC thrombus.

A multicenter retrospective study of nivolumab monotherapy in previously treated metastatic renal cell carcinoma patients: interim analysis of Japanese real-world data.

BACKGROUND: In a phase III clinical trial, CheckMate 025, treatment of metastatic renal cell carcinoma (mRCC) with nivolumab demonstrated superior efficacy over everolimus. However, as the clinical trial excluded patients with specific complications and poor performance status (PS), the effectiveness and safety of nivolumab in clinical practice, in which patients with various clinical complications are treated, is unclear. This study explored real-world nivolumab treatment in Japanese mRCC patients. METHODS: This is an interim analysis of a multicenter, non-interventional, medical record review study (minimum follow-up: 9 months). All eligible Japanese mRCC patients who first received nivolumab between February and October 2017 were included; data cut-off was April 2019. We analyzed nivolumab treatment patterns, efficacy (including overall survival, progression-free survival, objective response rate, and duration of response) and safety (including immune-related adverse events). RESULTS: Of 208 evaluable patients, 31.7% received nivolumab as fourth- or later line of treatment. At data cut-off, 26.9% of patients were continuing nivolumab treatment. The major reason for discontinuation was disease progression (n = 100, 65.8%). Median overall survival was not reached; the 12-month survival rate was 75.6%. Median progression-free survival was 7.1 months, the objective response rate was 22.6%, and median duration of response was 13.3 months. Patients who were excluded or limited in number in CheckMate 025, such as those with non-clear cell RCC or poor PS, also received benefits from nivolumab treatment. Immune-related adverse events occurred in 27.4% of patients (grade ≥ 3, 10.1%). CONCLUSION: Nivolumab was effective and well-tolerated in real-world Japanese mRCC patients. TRIAL REGISTRATION: UMIN000033312.

[Neoajuvant Chemotherapy with Gemcitabine and Cisplatin Plus S-1 for Primary Female Urethral Adenocarcinoma].

A 67-year-old female presented for evaluation of a left inguinal mass. Contrast-enhanced computed tomography revealed a tumor surrounding the urethra. Magnetic resonance imaging showed that the tumor had invaded the bladder neck on the anterior aspect of the urethra. The serum carbohydrate antigen 19-9 level was elevated. The clinical diagnosis was a primary adenocarcinoma of the female urethra (cT4N2M0). The initial treatment consisted of gemcitabine plus cisplatin (GC) and oral fluoropyrimidine (S-1). A total cysto-urethrectomy with anterior vaginal wall resection, pelvic and inguinal lymphadenectomy, and urinary diversion with ileal conduit formation were performed. The final diagnosis was urethral adenocarcinoma (ypT4ypN2, stage IV). Twelve months post-operatively, there was no evidence of recurrence or distant metastases.

[A Case of Extragonadal Germ Cell Tumor Treated by Induction Therapy with A Reduced Bep Regimen].

A 21-year-old man with chief complaints of left hypochondriac and chest pain was shown to have multiple masses in the lung, a pleural effusion in the right cavum thoracis, a mediastinal mass, and lymphadenopathy detected by computed tomographic scan. He was diagnosed with an extragonadal germ cell tumor based on pathologic findings from lung biopsies and elevation of the serum total human chorionic gonadotropin. He underwent a reduced chemotherapy regimen consisting of bleomycin, cisplatin, and etoposide (reduced BEP) to lower the risk of acute respiratory distress syndrome (ARDS), a manifestation of choriocarcinoma syndrome, which occurs at induction chemotherapy with the full-dose BEP regimen. Choriocarcinoma syndrome did not develop during chemotherapy, and he has been disease-free since salvage chemotherapy and subsequent retroperitoneal lymph node dissection.

Randomized controlled study of the efficacy and safety of continuous saline bladder irrigation after transurethral resection for the treatment of non-muscle-invasive bladder cancer.

OBJECTIVE: To evaluate the efficacy and safety of continuous saline bladder irrigation (CSBI) after transurethral resection of bladder tumour (TURBT) in patients with low- to intermediate-risk non-muscle invasive bladder cancer (NMIBC). PATIENTS AND METHODS: In this prospective randomized study, 250 patients with primary low- to intermediate-risk tumours were enrolled. Patients were randomly allocated to receive CSBI (2 000 mL/h for the first 1 h, then 1 000 mL/h for 2 h, followed by 500 mL/h for 15 h) or a single immediate instillation of mitomycin C (MMC) after TURBT. The primary endpoint was recurrence-free survival, and secondary endpoints were progression-free survival and adverse events. RESULTS: A total of 227 patients (114 in the CSBI group and 113 in MMC group) remained for analysis after exclusion criteria had been applied. The median follow-up period was 37 months. No significant differences in patient characteristics were observed between the groups. The 5-year recurrence-free rates for CSBI and MMC were 62.6% (95% confidence interval [CI] 0.49-0.73) and 70.4% (95% CI 0.59-0.78), respectively. Kaplan-Meier analysis of recurrence-free survival did not show any significant differences between the groups (log-rank test P = 0.53). Furthermore, there were no significant differences between the groups in terms of tumour progression rate and the median time to first recurrence. The incidence of adverse events was significantly lower in the CSBI group. CONCLUSIONS: The results show that CSBI after TURBT may be a treatment option for patients with low- to intermediate-risk NMIBC in terms of its prophylactic effect and safety.

A case of IgG4-positive plasma cell-rich tubulointerstitial nephritis in a kidney allograft mimicking IgG4-related kidney disease.

A 51-year-old woman received an ABO blood type-incompatible renal transplant. She was administered rituximab and basiliximab and underwent plasma exchanges for induction therapy, followed by administration of tacrolimus, mycophenolate mofetil and methylprednisolone as maintenance immunosupression therapy. A planned renal biopsy 2 years after transplantation revealed infiltration of plasma cells in the renal interstitium, although there was no 'storiform' fibrosis surrounding these cells. There were also no findings of rejection, BK virus nephropathy, or atypical plasma cells. Immunohistochemical stainings showed a large number of IgG4-positive plasma cells, most of which expressed kappa-type light chains. A CT scan showed a mass at the renal hilum. The serum IgG4 level was high. Based on these findings, the patient was suspected of having IgG4-related kidney disease. Nine months after the biopsy, her serum creatinine level increase to 1.56 mg/dL and the dose of methylprednisolone was therefore increased to 16 mg/day. Three months after this increase in steroid, a CT scan showed the hilum mass had disappeared. A follow-up biopsy 5 months later showed that infiltration of plasma cells in the renal interstitium had decreased markedly, although focal and segmental severely fibrotic lesions with IgG4-positive plasma cells were observed. Serum IgG4 levels decreased immediately after the increase in steroid dose and remained <100 mg/dL despite a reduction in methylprednisolone to 6 mg/day. Serum creatinine levels also remained stable at around 1.6 mg/dL. To our knowledge, this is the first report of IgG4-positive plasma cell-rich tubulointerstitial nephritis mimicking IgG4-related kidney disease after kidney transplantation.

[Urinary schistosomiasis: report of a case].

A 20-year-old unmarried Ghanaian man complaining of macroscopic hematuria and cystitis symptom was admitted to our institute. Abdominal ultrasound revealed a hyper echoic lesion in the entire bladder wall. Computed tomography showed a calcification of the whole bladder wall and of the left lower ureter. Flexible cystoscopy revealed many nodular masses, so-called 'bilharzial tubercles', at the trigone and posterior wall of the urinary bladder, and there was partial bleeding. Pathological examination revealed granuloma with many calcified eggs of schistosome haematobium. He was diagnosed with Bilharzial schistosomiasis and was treated with 1,500 mg of praziquantel for two days. However the therapeutic effect was insufficient. Therefore, he was treated with 2,400 mg of praziquantel for two days, and the symptoms disappeared.

Female pelvic organ-preserving robot-assisted simple cystectomy and intracorporeal ileal neobladder reconstruction on a young woman with Hunner-type interstitial cystitis.

Introduction: Cystectomy is the last treatment option for Hunner-type interstitial cystitis. However, consensus regarding optimal patient selection or treatment approaches is lacking. Case presentation: A 27-year-old woman presented to a regional hospital with bladder pain and frequent urination. Antimicrobial therapy was administered; however, her symptoms persisted and she was finally diagnosed with HIC. Multiple endoscopic fulgurations of Hunner's lesions with bladder hydrodistension or intravesical therapy were performed; however, the symptoms persisted. A urethral catheter was inserted 1 month before she visited our clinic because of a severely contracted bladder. We performed female pelvic organ-preserving robot-assisted simple cystectomy and intracorporeal ileal neobladder reconstruction. The patient's postoperative course was uneventful and her symptoms resolved. Conclusion: This is the first report of pelvic organ-preserving robot-assisted simple cystectomy and intracorporeal ileal neobladder reconstruction in a young woman with HIC.

Postoperative complications and determinant of selecting non intracorporeal urinary diversion in patients undergoing robot-assisted radical cystectomy: an initial experience.

Background: Robot-assisted radical cystectomy (RARC) with urinary diversion has become a standard surgical procedure because of its three-dimensional high-definition surgical field of view, flexibility, and stability. However, because of the highly complex steps of surgery, postoperative complications cannot be ignored. Methods: This retrospective, single-center, observational cohort study investigated the postoperative complications following RARC at a non-high-volume center in Japan. From August 2019 to March 2023, 50 consecutive patients who underwent RARC for histologically proven muscle-invasive bladder cancer (MIBC) or high-risk non-MIBC with an indication for radical cystectomy according to the Japanese Urological Association Guideline 2019 were included. Factors correlated with the selection of extracorporeal urinary diversion (ECUD) or cutaneous ureterostomy rather than intracorporeal urinary diversion (ICUD) for urinary diversion were also investigated. Results: In total, 33 (66%) and 31 (62%) patients experienced complications during the first 90 and 30 days after RARC, respectively. Among them, 19 (38%) and 18 (36%) patients developed Clavien-Dindo classification G2 complications, and 12 (24%) and 11 (22%) developed G3 or higher (major) complications during the first 90 and 30 days after RARC, respectively. The most common complications were gastrointestinal complications (26%) and urinary tract infections (22%). Nine patients (18%) underwent surgical intervention within 90 days of undergoing RARC. Higher infusion volume during the operations was significantly correlated with the occurrence of major complications within 90 days (P=0.025) and 30 days (P=0.0158) after RARC. Nineteen patients (38%) underwent non-ICUD. Twelve patients received ECUD as an ileal conduit or neobladder, and among them, three patients received ECUD due to intraabdominal adhesion for previous abdominal surgery or radiation, while four patients received ECUD ileal conduit due to comorbidities and advanced cases (palliative surgery) to shorten the surgery time. Conclusions: Surgical complications related to the initial experience with RARC at a non-high-volume center in Japan cannot be ignored. Although this complicated surgical procedure requires a learning curve to achieve a stable rate of much fewer major complications after RARC, careful assessment of patients' status before surgery and critical postoperative management may reduce complication rates more quickly, even at non-high-volume centers.

[A case of primary malignant lymphoma of the prostate with characteristic MRI findings].

Here, we report a case of malignant lymphoma (ML) of the prostate. A 77-year-old man was referred to our hospital with the chief complaint of left lumbago. Computed tomography imaging showed a large mass below the bladder, as well as left hydronephrosis resulting from infiltration of the mass. Magnetic resonance imaging (MRI) revealed enlargement and high-intensity of the whole prostate with diffusionweighted image. An enlarged, stony, hard prostate was palpable on digital rectal examination, but the prostate-specific antigen (PSA) level was 4.65 ng/ml. Since the patient developed urinary retention and macrohematuria, transurethral hemostasis and biopsy were performed. Histological findings and immunohistochemical studies revealed diffuse large B-cell non-Hodgkin's lymphoma (DLBCL). MRI is thought to play a critical role in localization diagnosis of Non-Hodgkin's lymphoma (NHL) since NHL demonstrates characteristic signs. Although the frequency of primary ML of the prostate is low, by paying careful attention to the characteristic signs on MRI and examination findings, we should consider a differential diagnosis of ML of the prostate, which is not a typical manifestation of prostatic cancer.