Hydrocalycosis is defined as cystic dilatation of a major calyx with a demonstrable connection to the renal pelvis and an epithelial lining of the cyst wall. Although this condition has long been known, there are no sufficient data concerning this pathology in the literature. In this study, we present two complicated hydrocalycosis--'pyocalycosis'--and discussed the therapeutic approaches.

We present a case of idiopathic retroperitoneal fibrosis (RPF) in a female patient of 45 years, obese (BMI = 39 kg/sqm), hypertensive since 2005, with diabetes mellitus treated with diet and diabetes insipidus in whom, during a routine control, the following has been found: serum creatinine 1.74 mg/dl, and an inflammatory syndrome associated with fever. Spiral-CT (Multi-slice-Sensation 64) scan shows retroperitoneal fibrosis in relation with periaortitis that affects the thoracic and abdominal aorta. RPF is extending perirenally and at the level of the renal hilum with subsequent calyceal dilations (hydrocalycosis) associated with left renal artery stenosis. The particularity of the case is represented by the perirenal and intrarenal evolution of fibrosis with left renal artery stenosis with moderate impairment of renal function reversible under treatment with Tamoxifen. This case, with chronic periaortitis subsequent to an extended aortic atherosclerosis with retroperitoneal fibrosis can be representative for the pathogenic relationship between atherosclerosis and fibrosis.

With the development of techniques for percutaneous access and equipment to disintegrate calculi, percutaneous nephroscopic surgery is currently used by many urologists and is the procedure of choice for the removal of large renal calculi and the management of diverticula, intrarenal strictures, and urothelial cancer. Although it is more invasive than shock wave lithotripsy and retrograde ureteroscopic surgery, percutaneous nephroscopic surgery has been successfully performed with high efficiency and low morbidity in difficult renal anatomies and patient conditions. These advantages of minimal invasiveness were rapidly perceived and applied to the management of ureteropelvic junction obstruction, calyceal diverticulum, infundibular stenosis, and urothelial cancer. The basic principle of endopyelotomy is a full-thickness incision of the narrow segment followed by prolonged stenting and drainage to allow regeneration of an adequate caliber ureter. The preferred technique for a calyceal diverticulum continues to be debated. Excellent long-term success has been reported with percutaneous, ureteroscopic, and laparoscopic techniques. Each approach is based on the location and size of the diverticulum. So far, percutaneous ablation of the calyceal diverticulum is the most established minimally invasive technique. Infundibular stenosis is an acquired condition usually associated with inflammation or stones. Reported series of percutaneously treated infundibular stenosis are few. In contrast with a calyceal diverticulum, infundibular stenosis is a more difficult entity to treat with only a 50-76% success rate by percutaneous techniques. Currently, percutaneous nephroscopic resection of transitional cell carcinoma in the renal calyx can be applied in indicated cases.

In patients with posterior urethral valves (PUV), severe unilateral vesicoureteral reflux (VUR) is one of the three conditions associated with preservation of renal function. Others are urinary ascites or urinoma in newborns and large congenital bladder diverticula. These conditions most likely provide a pop-off mechanism preventing the development of high intravesical pressure. Only 5% of patients with PUV and an associated pop-off mechanism will develop renal failure as opposed to 40 % of patients with PUV without a protective factor. We present a 3-year-old boy with posterior urethral valves and a severe right unilateral vesicoureteral reflux. He had PUV ablation with Mohan's valvotome and made satisfactory post operative recovery with indication on follow-up of preservation of renal function.

Bilateral hydrocalycosis secondary to radiographically demonstrated bilateral infundibular stenosis required a left nephrectomy in an 18-year-old young man. The infundibular narrowing was due to marked hyperplasia of the submucosal smooth muscle. Scattered within the hypertrophic smooth muscle were rare spindled CD117-positive interstitial cells, similar to the cells responsible for peristaltic pacemaker activity within the gastrointestinal tract. The admixture of CD117 cells suggests this is a true muscular hyperplasia rather than a leiomyomatosis. The stimulus to the hyperplasia is unknown.

Although many causes of curvilinear renal calcifications have been described, calcified hydrocalycosis mimicking hydatid cyst has not previously been reported. We report a case of hydrocalycosis which was appeared as a curvilinear calcified cystic lesion resulted from staghorn calculus associated with xanthogranolomatous pyelonephritis (XGPN) on intravenous pyelography (IVU) and computed tomography (CT).

We present a very rare case of gigantic hydrocalycosis which was caused by an obstructed stone. It was so large that it displaced the rest kidney into the contralateral lumbar fossa giving the appearance of a crossed ectopic kidney.

The paper is concerned with comparison of the results of ultrasound and x-ray investigation in 110 patients with urolithiasis. A possibility was established to diagnose roentgenonegative concrements in the kidneys and pelvicalyceal system with the help of ultrasound echography. The results of x-ray investigation were more reliable for the localization of uretero- and cystoliths. Ultrasound echography in such patients permitted the detection of complications (hydrocalycosis and hydronephrosis) as well as the assessment of the time course of complications in the postoperative period.

A retrospective study was done on 64 patients who received staged extracorporeal shock wave lithotripsy (ESWL) monotherapy for complete renal staghorn calculi. We used laboratory-proven stone components and a regular postoperative follow-up for a minimum of 6 months. There were 46 women and 18 men. The ages ranged from 19 to 75 years (mean 48.5 years). The number of ESWL sessions ranged from 1 to 4, with a mean of 2.1 sessions. The mean cumulative hospital stay was 13.3 days (range: 6-26 days). Successful treatments were defined as debulking over 90% of the stone burden and residual fragments of less than 3 mm in the longest diameter without obstruction 6 months post-treatment. A success rate of 86% was achieved in patients who had normal or minimal hydrocalycosis and only a 14.3% success rate for the patients with moderate to severe hydrocalycosis (p less than 0.005). Five of the patients with radiant calcium oxalate monohydrate had an unfavorable outcome. The best results were observed in the patient group of magnesium ammonium phosphate/apatite with normal to minimal hydrocalycosis (94.4% successful). The stone-free rate in this series was 51.6% at 6 months posttreatment. Being the least invasive, staged ESWL monotherapy is one of the better alternatives for the treatment of complete renal staghorn calculi in a select patient group.

The Soviet-made device "URAT-P" for remote lithotripsy was used for the treatment of urolithiasis in children aged from 22 months to 14 years who suffered from various clinical patterns of urolithiasis with solitary or dendritic calculi. Out of 64 treated persons, 21 children had undergone 1-2 surgeries for the disease. The majority of them had pains and frequent aggravations of pyelonephritis. Excretory urography revealed the signs of hydronephrosis and hydrocalycosis. There was no need for additional adjustments to perform the procedure in patients with a height of under 75 cm. The authors employed erosive operating conditions of a shock-wave generator for lithotripsy in case of large or dendritic calculi and to avoid preliminary renal drainage. One treatment session was a success in 43 patients, 2 sessions were needed for 15, 3 for 4 and 4 for 2 patients. A beneficial effect (total disintegration and fragmental discharge) was reached in 64 (98.4%) of the patients. Partial disintegration was recorded only in 1 patient who was exposed to 2 sessions. Radioisotope, immunological, ultrasonic, and biochemical investigations failed to reveal inhibition of the renal functional parameters after remote lithotripsy. No renal injuries associated with hematogenesis were revealed in the parents. The signs of hematuria were observed in the first portion of the postoperative urine only. The only serious complication calling for close attention is acute pyelonephritis observed in 6 patients, one case requiring a surgical application of nephrostoma.

Infundibulopelvic dysgenesis is an obstructive process of the pyelocalyceal system that is responsible for a spectrum of congenital renal disorders. The site and degree of narrowing in the infundibulopelvic system produce the various congenital anomalies like hydrocalycosis, calyceal diverticula, ureteropelvic junction stenosis, and multicystic kidney. A classification with illustrative cases is presented showing a common pathogenesis of these congenital obstructive anomalies.

We have experienced 7 cases of multicystic kidney. The latest two cases, etiologically of interest, are reported herein with special reference to its embryogenesis. Case 6: A 4-year-old girl was referred to our clinic for further evaluation of mild azotemia and nonvisualization of left kidney. Left kidney was strongly thought to be multicystic kidney from abdominal CT, whereas her contralateral kidney exhibited hydrocalycosis resembling infundibular stenosis with diminished calyceal numbers. Nephrectomy of her left kidney was performed and histological studies confirmed renal dysplasia (primitive duct, metaplastic cartilage, etc.). Case 7: A 7-year-old girl was referred to Hakodate Kyokai Hospital for the evaluation of azotemia and low stature. Her right kidney was not visualized on IVP and her left kidney exhibited hydronephrosis with diminished calyceal numbers. Her right kidney was diagnosed as multicystic kidney on CT-scan. Pyeloplasty of her left kidney was performed. Multicystic kidney is a rather rare congenital disease. Association of various anomalies in contralateral kidney has been emphasized as well as the notion that infundibulopelvic stenosis is a linked in the clinical spectrum extending from cystic dysplasia of the kidney to hydronephrosis. Our last two cases seem to be included in this category of obstruction theory. As shown by microdissection technique (Potter), however, severe ampullary inhibition early in fetal life is also an attractive hypothesis. Diminished calyceal number of contralateral kidneys seen in our recent two cases is compatible with possibility of ampullary damage. Recent experimental study also showed that renal dysplasia is not solely caused by simply mechanical obstruction to urinary drainage, even when the obstruction is imposed at an early stage of renal development.

The appearances of 34 parapelvic cysts diagnosed by computed tomography (CT) in 29 patients are described. The majority were found as an incidental finding but some caused hydrocalycosis and, in one instance, hypertension. Their etiology, CT features, and differential diagnosis are discussed. The specificity of CT in these cases eliminates the need for invasive diagnostic procedures.

Hydrocalycosis is the progressive cystic dilatation of a major calyx due to infundibular obstruction. Two cases of hydrocalycosis are herein presented and several diagnostic procedures are discussed. A correct diagnosis can be made by proper use of newer radiographic techniques. Treatment depends upon the etiological and complicating factors.