Impact of Microscopic Wall Invasion of the Renal Vein or Inferior Vena Cava on Cancer-specific Survival in Patients with Renal Cell Carcinoma and Tumor Thrombus: A Multi-institutional Analysis from the International Renal Cell Carcinoma-Venous Thrombus Consortium.

BACKGROUND: Microscopic vein invasion (MVI), with local destruction and invasion of the endothelium by tumor, is of controversial predictive value in renal cell carcinoma (RCC). OBJECTIVE: To assess the impact of venous extension and wall invasion in RCC on survival. DESIGN, SETTING, AND PARTICIPANTS: Data for 1023 RCC patients with vena cava thrombus treated with radical nephrectomy and complete tumor thrombectomy were collected within a prospectively maintained international consortium (1995-2012). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The Kaplan-Meier method and univariable and multivariable Cox regression analyses were used to assess the impact of MVI on cancer-specific survival (CSS). The main two variables of interest were microscopic renal vein wall invasion (MRVI) and microscopic vena cava wall invasion (MVCI). RESULTS: MRVI was found in 725 cases (70.9%) and MVCI in 230 (22.5%). Patients with MRVI had larger tumors (p=0.005), longer hospital stay (p<0.001), higher clinical stage 0.039), higher Fuhrman grade (p=0.028), and more frequent fat invasion. Presence of MVCI was associated with larger tumors (p<0.001), longer hospital stay (p<0.001), higher clinical stage (p<0.001), lymph node involvement (p=0.045), higher Fuhrman grade (p<0.001), and higher thrombus level (p<0.001). With median follow-up of 52 mo, overall 5-yr CSS was 57.4%. Multivariable analysis showed that presence of MRVI was an independent factor related to CSS (hazard ratio 2.24, 95% confidence interval 1.24-3.59, p=0.006). The main limitation was the inability to report MVI percentages. CONCLUSIONS: Patients with MRVI experience significantly worse survival outcomes after radical nephrectomy and tumor thrombectomy. Consideration of MRVI at final pathology is appropriate to improve decision-making for risk-adapted follow-up. PATIENT SUMMARY: The behavior of locally advanced renal cell carcinoma (RCC) depends on clinical and pathologic factors. Analysis revealed that RCC patients with microscopic renal vein wall invasion experience significantly worse cancer-specific survival.

Venous communication between the right and left kidneys: a rare anatomic variation / Comunicación venosa entre los riñones derecho e izquierdo: una rara variación anatómica

Renal vascular anatomic variations, especially of the renal arteries, have been observed in about 20-30 percent of cases, which are very often verified in the left antimere. These variations showed two or three renal arteries stemming directly from the aorta. These anatomic variations have been considered extremely important risk factors in surgical proceedings by different authors. The dissection of a cadaver showed an uncommon venous feature in addition to renal artery variation, specially, in the left antimere. A direct venous communication between left and right kidneys was verified without there being any relation to the inferior cava vein or common iliac veins. Thus, the knowledge of blood vessel anatomic variation is an important element to improve surgical techniques as well as to provide precise analyses of urological and radiological proceedings in different renal diseases. Specially, taking into consideration that hard traction of the renal pedicle could rupture the vessels, leading to lethal hemorrhaging.

Se han observado variaciones anatómicas vasculares renales, especialmente de las arterias renales, en una frecuencia alrededor del 20 a 30 por ciento de los casos, cuya incidencia se verifica a menudo en el antímero izquierdo. En estas variaciones, de acuerdo con lo que se notó, dos o tres arterias renales provenían directamente de la aorta. Distintos autores han considerado que estas variaciones anatómicas son factores de riesgo extremadamente importantes en los procedimientos quirúrgicos. En esta investigación, por medio de la disección de un cadáver, se observó una característica venosa rara, además de la variación de la arteria renal, especialmente en el antímero izquierdo. Se verificó una comunicación venosa directa entre los ríñones izquierdo y derecho, pese al hecho que no sea común cualquier relación con la vena cava inferior o las venas ilíacas comunes. Así, el conocimiento de la variación anatómica del vaso sanguíneo es un elemento importante para implementar técnicas quirúrgicas, así como proporcionar análisis exactos de procedimientos urológicos y radiológicos en diversas enfermedades renales, pues se debe considerar además que la tracción dura del pedículo renal podría romper los vasos y ocasionar una hemorragia mortal.

Pathogenesis of the glomerular abnormality in cyanotic congenital heart disease.

We present evidence of 2 distinct glomerular abnormalities in cyanotic congenital heart disease--vascular and nonvascular--each believed to reflect a distinct pathogenesis. Glomeruli from both kidneys were studied with light microscopy in 13 necropsied cyanotic patients and in 8 controls. The vascular study characterized hilar arteriolar dilatation, capillary diameter, glomerular diameter, and capillary engorgement with red blood cells. The nonvascular study characterized juxtaglomerular cellularity, mesangeal cellularity, mesangeal matrix, focal interstitial fibrosis, and megakaryocytic nuclei per cm2 of renal cortex. There was a significant increase in each of the above vascular and nonvascular items of interest relative to controls. Electron microscopy identified whole megakaryocytes with their cytoplasm in glomeruli. The vascular abnormality is believed to result from intraglomerular release of nitric oxide. The nonvascular abnormality is believed to result from platelet-derived growth factor and transforming growth factor-beta.

The valva portalis renalis in the duck (Anas platyrhynchos).

The morphology of the valva portalis renalis of the duck was investigated, using histological, SEM and TEM techniques. The wall thickness of the vena iliaca externa, the vena portalis renalis caudalis, the vena iliaca communis and the vena renalis caudalis was morphometrically evaluated. The blood pressure in these veins was measured using a three-way H2O manometer. The valva portalis renalis was composed primarily of epithelioid cells and lined with endothelium. Throughout the entire valva there was a dense complex of nerve structures made up of fibers and fiber bundles which also extended beneath the endothelium of the valva and around the subendothelial epithelioid cells. The wall thicknesses of the veins supplying the renal portal system (vena iliaca externa and vena portalis renalis caudalis) were greater than those of the vessels collecting the renal refluent venous blood (vena iliaca communis and vena renalis caudalis). In addition, the blood pressure values taken in the vena iliaca externa and the vena portalis renalis caudalis were much higher than those in the vena iliaca communis and the vena renalis caudalis. The above observations suggest that the renal portal system works at higher blood pressure levels than the general venous system and that the valva portalis renalis regulates its aperture in order to maintain a constant blood pressure and a continuous blood flow in the renal portal system vessels, hence avoiding damage to the renal parenchyma caused by pressure overloads.

Morphological studies of the valves of the kidney vein in domestic swine.

It was established macroscopically that 37.5% of the renal veins investigated possess valves. Valves were observed on both sides, but predominantly on the left side of the kidneys (14.58%). Some valves were also observed in the main branches of the renal veins. The structure of the valves was studied with the use of light and electron microscopy. The most important finding was the observation of mast cells in the valves. This is probably a common biological phenomenon, since mast cells have been observed in the cardiac valves and the wall of the renal artery and vein.

Additional renal veins: incidence and morphometry.

Modern surgical and radiological techniques dictate a reappraisal and definition of the renal venous anatomy. The purpose of this study was to investigate the incidence and morphometry of additional renal veins. One hundred fifty-three morphologically normal en bloc renal specimens were randomly selected from post-mortem examinations. Single additional renal veins were common on the right side (26%), while it was rare on the left side (2.6%). Second additional renal veins occurred infrequently on the right side (5%). Since additional renal veins may be encountered more than occasionally, it is worthwhile emphasizing their presence particularly to the transplant surgeon and the angiologist.

[Morphofunctional changes in the kidneys in venous stasis during early period and during recovery of blood outflow from the organ]. / Morfofunktsional'nye izmeneniia v pochkakh pri venoznoi zastoe v rannie sroki i v period vosstanovleniia ottoka krovi ot organa.

Short-term (3 days) 50% constriction of the left renal vein with the following recovery of outflow from the kidneys (30 days) was carried out on (180-210 g) white mongrel adult rats of both sexes. By means of light optical, electronmicroscopic and radioisotopic methods it was established that venous haemostasis in early period leads to the slowing-down of regional renal circulation and the development of dystrophic changes both in the wall of intrarenal veins and in the edge and cubical cells of proximal and distal departments of nephron. With the recovery of renal circulation from kidneys canal-vascular formation acquire normal morphological structure. Compensatory-adaptive processes in the separate parts are noted.

The luminal aspect of intrarenal arteries and veins in the rat as revealed by scanning electron microscopy.

The luminal aspect of intrarenal arteries and veins in the rat has been investigated by scanning electron microscopy (SEM). The endothelium of the intrarenal arteries consists of spindle-shaped cells and forms longitudinally running ridges which correlate with the folding pattern of the underlying internal elastic lamina. Intraarterial "cushions" were found at the origins of afferent arterioles from arcuate arteries and along the entire course of interlobular arteries. The intrarenal veins are made up of a thin, extensively fenestrated epithelium equal to that of peritubular capillaries. The outer aspect of the endothelium contacts adjacent tubules as closely as the capillaries proper. Thereby, the luminal aspect of the veins exhibits a striking "tubule relief" created by the underlying tubules. This wall structure of the intrarenal veins suggest that diameter and shape of the veins are probably highly dependent on the surrounding interstitial pressure.

Renal microvasculature of the black bear (Ursus americanus).

This study of the Black bear (Ursus americanus) was undertaken to provide basic information related to structural modifications in the renal microvasculature that might provide insight into the drastic alteration in renal urinary output that occurs during winter sleep. Vascular casts, as well as light microscopy and scanning electron microscopy, were used to study the vascular components of the juxtaglomerular complex and related vessels. Histologically, arterial cushions were readily identified at the origin of the afferent arterioles. In the area of the juxtaglomerular complex, the wall of the afferent arteriole appeared to be highly modified. The smooth muscle cells at this site demonstrated a change in morphology and orientation, and the diameter of the arteriole was altered. The pattern of the vascular casts at the origin of the afferent arteriole varied from that portion at the glomerulus, suggesting a modification of the vascular wall near the renal corpuscle. Although the morphology of the renal microvasculature of the Black bear is similar to that of other mammals in some aspects, it is dissimilar to that of other carnivores and of the human kidney in that there are structural modifications of the afferent arteriole that may contribute to a reduction of blood flow to the nephron during winter sleep.

Renal vascular smooth muscle proliferation in neurofibromatosis.

An unusual vascular lesion was seen in a 14-year-old white boy with renal vascular hypertension and neurofibromatosis. Microscopically, nodular intimal and medial proliferations of spindle-shaped cells involved arteries, arterioles, and veins of all caliber within the renal parenchyma. Immunoperoxidase studies indicated these cells to have characteristics of smooth muscle, and this finding was confirmed by ultrastructural examination. Despite the generalized nature of the process in the biopsy sample, the patient's hypertension responded well to surgical treatment.

Scanning electron microscopy of vascular corrosion casts in comparative studies on renal vascular structure.

In comparative microcorrosion casting studies on renal vascular systems the following demands should be met: The preparation procedure (anaesthesia, operation, flushing of the blood vascular system, ...) should be in accord with the specific physiological properties of the animal under investigation and the casting procedure (injection, curing, maceration, ...) should be kept constant as far as possible. If these points are considered, comparative data, even of quantitative nature, can be obtained from corrosion casts. Examples of results at the organ, single vessel and intercellular level as well as correlation of the results with physiological data are given.

Idiopathic microscopic polyarteritis nodosa: ultrastructural observations on the renal vascular and glomerular lesions.

Although the glomerulonephritis (GN) and renal vasculitis in polyarteritis nodosa (PAN) are generally considered to be immune-mediated, the pathogenesis of the renal injury and the role of immune complex (IC) deposition are unclear. To better define the nature of the glomerular and vascular injury in PAN, we performed a detailed ultrastructural study of 27 renal biopsies from 20 patients with histologically confirmed PAN of the microscopic or overlap (microscopic/macroscopic) type. A total of 48 arteries and arterioles were studied ultrastructurally, including 20 vessels with recognizable vasculitis in 1 micron-thick survey sections. By immunofluorescence, glomerular and vascular immunoglobulin deposits were generally scanty, primarily located in areas of necrosis or sclerosis. Fibrinogen, C3 and C1 were more commonly detected, often in the absence of demonstrable immunoglobulin. By electron microscopy, discrete electron-dense deposits of probable immune-type were found in the glomeruli of five initial biopsies. No electron-dense deposits were identified in any of the arteries or arterioles studied. In both glomeruli and vessels, endothelial injury and subendothelial fibrin deposition were the earliest detectable ultrastructural changes. The pathogenetic implications of these findings are discussed.

Ultrastructural evidence for a reabsorptive role by intrarenal veins.

Intrarenal veins, although known to have thin walls, are considered to be simple conducting vessels. Using light- and electron microscopy, the distribution and structure of named intrarenal veins was examined qualitatively and quantitatively in rat kidneys fixed by retrograde arterial perfusion. Although the venous system follows the pattern of arterial branching in general, a class of intracortical veins similar in appearance to interlobular veins but without a companion artery was found in the present study. It is suggested that these vessels be designated intralobular veins. Structurally, we have found intrarenal veins to be surprisingly similar to peritubular capillaries both in respect to their spatial relations to renal tubules as well as ultrastructurally. Like peritubular capillaries, the majority of the wall of intrarenal veins is intimately apposed to renal tubules. This fraction decreases centrally, values of 0.83 being obtained in intralobular veins, 0.69 in interlobular veins, and 0.56 in arcuate veins. The walls of intrarenal veins are comprised of little more than an endothelium, which, like peritubular capillaries, is remarkable for its thinness, high density of fenestrae, and lack of extraintimal elements. Endothelial thickness was not significantly greater in either interlobular or arcuate veins than in peritubular capillaries; the fenestrae were, however, about twice as frequent in peritubular capillaries as in interlobular or arcuate veins and 35 times more frequent than in interlobar veins. The size and numerical and volume densities of uncoated endocytotic vesicles did not differ significantly between peritubular capillaries and any of the intrarenal veins. Based on their marked qualitative and quantitative similarities to peritubular capillaries, we conclude that, like the latter, intrarenal veins are capable of sustaining passive transport between plasma and interstitium.

Renal microcirculation of the bullfrog, Rana catesbeiana. A scanning electron microscope study of vascular casts.

The microcirculation of the bullfrog kidney was studied by scanning electron microscopy of the corrosion casts. The bullfrog kidney derives its blood supply from a dual origin: one is from the posterior half of the body via the renal portal veins and the dorso-lumbar veins, the other is from the urogenital arteries. The renal portal veins are linked with the hepatic portal system through the anterior abdominal vein which might serve as a transport route of the potentially renal portal blood to the kidney. The glomerulus consists of several lobules of anastomosing capillaries which are intercalated between the afferent and efferent arteriole. The efferent arteriole of the glomerulus runs some distance ventrad without branching to join the peritubular sinusoidal capillaries near the ventral surface of the kidney. Usually each glomerulus has a single efferent arteriole, but double efferent arterioles may rarely occur. Near the medial border of the kidney the glomeruli are small, and laterally they become progressively larger.

Segmental differentiations of cell junctions in the vascular endothelium. Arteries and veins.

A systematic survey of endothelial junctions in elastic (aorta) and muscular (mesenteric) arteries and in medium (renal and mesenteric) and large (cava inferior) size veins has been carried out in the rat using freeze-cleaved preparations. The arterial endothelium is provided with a complex of occluding and communicating junctions (gap junctions) comparable to, though less elaborate than, that described in arterioles. The particles of the occluding junctions behave like "single unit" particles and have the tendency to remain on B faces upon membrane cleavage. In the venous endothelium the junctions take the form of long occluding junctions with few associated communicating junctions (maculae communicantes). As in arterial endothelium, the junctional particles appear preferentially on B faces in cleaved preparations. These structures, although continuous over long distances, are interrupted focally by areas in which the junctional elements are similar to those found in venules: the ridges and grooves are short, discontinuous, randomly distributed along the general line of cell contact, and often particle-free. In muscular arteries two unusual types of junctions are encountered. Both are disposed in loops over short distances along the perimeter of the cell. One type appears to be a strectched-out version of the usual combination of occluding and communcating junctions of the arterial endothelium (this type is also occasionally encountered in the venous endothelium). The other type is reminiscent of the septate junctions found in the epithelia of invertebrates but the apparent similarity remains to be checked by further work.