Near-infrared spectroscopy as a novel method of ex vivo bladder cancer tissue characterisation.

OBJECTIVE: To evaluate near-infrared (NIR) spectroscopy in differentiating between benign and malignant bladder pathologies ex vivo immediately after resection, including the grade and stage of malignancy. PATIENTS AND METHODS: A total of 355 spectra were measured on 71 bladder specimens from patients undergoing transurethral resection of bladder tumour (TURBT) between April and August 2022. Scan time was 5 s, undertaken using a portable NIR spectrometer within 10 min from excision. Specimens were then sent for routine histopathological correlation. Machine learning models were applied to the spectral dataset to construct diagnostic algorithms; these were then tested for their ability to predict the histological diagnosis of each sample using its NIR spectrum. RESULTS: A two-group algorithm comparing low- vs high-grade urothelial cancer demonstrated 97% sensitivity, 99% specificity, and the area under the receiver operating characteristic curve (AUC) was 0.997. A three-group algorithm predicting stages Ta vs T1 vs T2 achieved 97% sensitivity, 92% specificity, and the AUC was 0.996. CONCLUSIONS: This first study evaluating the diagnostic potential of NIR spectroscopy in urothelial cancer shows that it can be accurately used to assess tissue in an ex vivo setting immediately after TURBT. This offers point-of-care assessment of bladder pathology, with potential to influence the extent of resection, reducing both the need for re-resection where invasive disease may be suspected, and also the potential for complications where extent of diagnostic resection can be limited. Further studies utilising fibre-optic probes offer the potential for in vivo assessment.

Mechanism of urosepsis: relationship between intrarenal pressures and pyelovenous backflow.

To document the histological changes observed in renal units subjected to elevated intrarenal pressures (IRPs) and postulate the possible mechanisms of infectious complications after ureteroscopy. MATERIALS AND METHODS: Ex vivo studies were performed on porcine renal models. Each ureter was cannulated with a 10-F dual-lumen ureteric catheter. A pressure-sensing wire was inserted through one lumen and with the sensor positioned in the renal pelvis for IRP measurement. Undiluted India ink stain was irrigated through the second lumen. Each renal unit was subjected to ink irrigation at target IRPs of 5 (control), 30, 60, 90, 120, 150, and 200 mmHg. Three renal units were subjected to each target IRP. After irrigation, each renal unit was processed by a uropathologist. Macroscopically, the amount of renal cortex stained by ink was calculated as a percentage of the total perimeter. Microscopically, presence of ink reflux into collecting ducts or distal convoluted tubules, and pressure-related features, was noted at each IRP. RESULTS: Signs of pressure, as represented by collecting duct dilatation, was first observed at 60 mmHg. Ink staining was consistently observed in the distal convoluted tubules at IRPs ≥60 mmHg, and all renal units above this pressure showed renal cortex involvement. At ≥90 mmHg, ink staining was observed in venous structures. At 200 mmHg, ink staining was observed in supportive tissue, venous tributaries in the sinus fat, peritubular capillaries, and glomerular capillaries. CONCLUSION: Using an ex vivo porcine model, pyelovenous backflow occurred at IRPs of ≥90 mmHg. Pyelotubular backflow occurred when irrigation IRPs were ≥60 mmHg. These findings have implications for the development of complications after flexible intrarenal surgery.

Rare presentation of a clear cell renal cell cancer metastasis to the contralateral testicle: A case report.

Renal cell carcinoma metastases to the testes are a rare occurrence, with less than 50 described in the literature. We describe a man who presented with a metastasis in his contralateral testicle five years after nephrectomy for clear cell renal cell carcinoma, as well as a review of the available literature. This case highlights the diagnostic challenges associated with this presentation.

Spindle cell tumours of the ureter: Operation or observation?

We describe a rare case of inflammatory spindle cell tumour of the ureter in a patient who presented with renal colic and macroscopic haematuria. Pyeloscopy revealed a partially obstructing mass at the proximal right ureter which confirmed a myofibroblastic tumour on biopsy. Radical nephrectomy was performed which confirmed a spindle cell tumour of the ureter confined to the resection margins. Follow-up imaging in 12 months did not illustrate recurrence or metastasis. The decision to perform a nephrectomy was due to the limited experience with this tumour. Reports illustrate that this tumour is unlikely to metastasize, and thus be managed conservatively.

Zinc preconditioning protects against renal ischaemia reperfusion injury in a preclinical sheep large animal model.

Ischaemia-reperfusion injury (IRI) during various surgical procedures, including partial nephrectomy for kidney cancer or renal transplantation, is a major cause of acute kidney injury and chronic kidney disease. Currently there are no drugs or methods for protecting human organs, including the kidneys, against the peril of IRI. The aim of this study was therefore to investigate the reno-protective effect of Zn2+ preconditioning in a clinically relevant large animal sheep model of IRI. Further the reno-protective effectiveness of Zn2+ preconditioning was tested on normal human kidney cell lines HK-2 and HEK293. Anaesthetised sheep were subjected to uninephrectomy and 60 min of renal ischaemia followed by reperfusion. Sheep were preconditioned with intravenous injection of zinc chloride prior to occlusion. Serum creatinine and urea were measured before ischaemia and for 7 days after reperfusion. HK-2 and HEK293 cells were subjected to in vitro IRI using the oxygen- and glucose-deprivation model. Zn2+ preconditioning reduced ischaemic burden determined by creatinine and urea rise over time by ~ 70% in sheep. Zn2+ preconditioning also increased the survival of normal human kidney cells subjected to cellular stress such as hypoxia, hydrogen peroxide injury, and serum starvation. Overall, our protocol incorporating specific Zn2+ dosage, number of dosages (two), time of injection (24 and 4 h prior), mode of Zn2+ delivery (IV) and testing of efficacy in a rat model, a large preclinical sheep model of IRI and cells of human origin has laid the foundation for assessment of the benefit of Zn2+ preconditioning for human applications.

Primary malignant melanoma of the urinary bladder and ureter.

Primary malignant melanoma of the urinary bladder is a rare lesion. We report the case of a 78-year-old male with no previous history of cutaneous melanoma who presented with hematuria. Further investigation with imaging and cystoscopy raised suspicion of a primary bladder and ureteric melanoma, which had subsequently metastasized. This was confirmed with histological assessment and a thorough search for alternative primary lesions. Unfortunately, our patient passed away prior to receiving any oncological treatment for his metastatic melanoma, underscoring both the high mortality of this lesion and the need for a consensus on definitive treatment.

Hypopharyngeal large cell neuroendocrine carcinoma.

Neuroendocrine carcinoma (NEC) of the head and neck is rare. We report a case of a 56-year-old man with a 6-week history of dysphagia, a neck mass and weight loss. He was diagnosed with a hypopharyngeal large cell NEC (LCNEC) with metastases to multiple sites. He received two cycles of cisplatin and etoposide. Subsequent restaging scan revealed progressive disease. The patient declined further chemotherapy and died shortly after. This is the third case of LCNEC of hypopharynx reported in the English literature and the first to progress on platinum-based chemotherapy. Although LCNEC of the head and neck is still classified as an atypical carcinoid, there is increasing evidence it is a distinct clinicohistopathological entity that carries an especially poor prognosis. Currently, there is a paucity of data to guide treatment of this rare malignancy.