Renal Cell Carcinoma with Unusual Metastasis to the Small Intestine Manifesting as Extensive Polyposis: Successful Management with Intraoperative Therapeutic Endoscopy

We present here a rare clinical case of a 53-year-old gentleman with metastasis from renal cell carcinoma (RCC) to the small intestine presenting with extensive polyposis and massive gastrointestinal bleeding which was successfully managed with intraoperative endoscopic polypectomy and segmental small bowel resection. The patient presented with melena 2 weeks after right nephrectomy for RCC. Capsule endoscopy found extensive polyposis throughout the small bowel, and the histological features confirmed the diagnosis of metastatic RCC. The patient eventually underwent laparotomy with intraoperative endoscopy of the entire small bowel. Most of the polyps were removed by snare polypectomy. Three segments of the small bowel with extensive transmural involvement had to be resected with primary anastomosis. In the 2 months following his surgery, the patient had no further evidence of gastrointestinal bleeding. The decision of meticulously removing close to 100 polyps by intraoperative endoscopy prevented the patient from requiring total small bowel resection and lifelong dependence on parenteral nutrition. In conclusion, gastrointestinal bleeding in a patient with known RCC should always trigger full gastrointestinal work-up including capsule endoscopy and, if necessary, double balloon enteroscopy

Afferent arteriolopathy and glomerular collapse but not segmental sclerosis induce tubular atrophy in old spontaneously hypertensive rats

In chronic renal disease, the temporal and spatial relationship between vascular, glomerular and tubular changes is still unclear. Hypertension, an important cause of chronic renal failure, leads to afferent arteriolopathy, segmental glomerulosclerosis and tubular atrophy in the juxtamedullary cortex. We investigated the pathological changes of hypertensive renal disease in aged spontaneously hypertensive rats using a large number of serial sections, where we traced and analyzed afferent arteriole, glomerulus and proximal tubule of single nephrons. Our major finding was that both afferent arteriolopathy and glomerular capillary collapse were linked to tubular atrophy. Only nephrons with glomerular collapse (n = 13) showed tubules with reduced diameter indicating atrophy [21.66 ± 2.56 μm vs. tubules in normotensive Wistar Kyoto rats (WKY) 38.56 ± 0.56 μm, p < 0.05], as well as afferent arteriolar wall hypertrophy (diameter 32.74 ± 4.72 μm vs. afferent arterioles in WKY 19.24 ± 0.98 μm, p < 0.05). Nephrons with segmental sclerosis (n = 10) did not show tubular atrophy and tubular diameters were unchanged (35.60 ± 1.43 μm). Afferent arteriolar diameter negatively correlated with glomerular capillary volume fraction (r = −0.36) and proximal tubular diameter (r = −0.46) implying reduced glomerular and tubular flow. In line with this, chronically damaged tubules showed reduced staining for the ciliary protein inversin indicating changed ciliary signalling due to reduced urinary flow. This is the first morphological study on hypertensive renal disease making correlations between vascular, glomerular and tubular components of individual nephron units. Our data suggest that afferent arteriolopathy leads to glomerular collapse and reduced urinary flow with subsequent tubular atrophy

Comparison of the renal cortex and the medulla for antibody mediated rejection

Objectives The presence of the peritubular capillaritis and its extent are important for diagnosis of the antibody-mediated rejection in kidneys. However, it is recommended that peritubular capillaritis should only be scored in the cortex. This study aims to focus on peritubular capillaritis scoring both in the cortex and the medulla to understand the value of the medulla in the diagnosis of antibody-mediated rejection. Methods Fifty-one allograft renal biopsy were re-evaluated for peritubular capillaritis, C4d and acute tubular injury, separately for the cortex and the medulla according to the Banff. Results Seventeen cases (33.3%) had peritubular capillaritis both in the cortex and the medulla and three (5.9%) cases had peritubular capillaritis only in the cortex while five (9.8%) cases had only in the medulla. Eighteen (35%) of the cases had C4d staining both in the cortex and the medulla and 14 (27.5%) cases had C4d positivity only in the cortex and 18 (35.3%) cases only in the medulla. Twenty-three (45%) cases had acute tubular injury both in the cortex and the medulla and 31 (60.7%) cases had acute tubular injury only in the cortex and 23 (45.1%) cases had only in the medulla. The sensitivity, specificity, positive and negative predictive values of medullar peritubular capillaritis predicting cortical peritubular capillaritis were 85.7%, 86.7%, 81.8% and 89.7%, respectively. Conclusion In case of absence of the cortical tissue, medulla can be used as a reference for antibody-mediated rejection considering the morphological features, results of donor-specific antibody and renal function tests