Hemorrhagic Renal Cyst Research Articles

Case of the Season: Hemorrhagic Renal Cyst Mimicking a Cystic Renal Neoplasm

An 81-year-old male with a history of chronic kidney disease, prostatic adenocarcinoma, metastatic melanoma, and Waldenström macroglobulinemia presented with acute kidney injury and dysuria. Initial renal ultrasound revealed a complex left renal cystic lesion, which was subsequently followed up on magnetic resonance imaging (MRI). Its complex appearance coupled with apparent nodularity suggested a cystic renal cell carcinoma; however, subsequent MRI revealed that active hemorrhage explained the complex appearance. A hemorrhagic renal cyst can be a diagnostic conundrum in such a scenario and should be considered in the differential diagnosis.

The Relationship Between Hemorrhagic Renal Cysts and Renal Function in Polycystic Kidney Disease

The Relationship Between Hemorrhagic Renal Cysts and Renal Function in Polycystic Kidney Disease

Hemorrhagic Cysts and Other MR Biomarkers for Predicting Renal Dysfunction Progression in Autosomal Dominant Polycystic Kidney Disease.

Screening for rapidly progressing autosomal dominant polycystic kidney disease (ADPKD) is necessary for assigning and monitoring therapies. Height-adjusted total kidney volume (ht-TKV) is an accepted biomarker for clinical prognostication, but represents only a small fraction of information on abdominal MRI. To investigate the utility of other MR features of ADPKD to predict progression. Single-center retrospective. Longitudinal data from 186 ADPKD subjects with baseline serum creatinine, PKD gene testing, abdominal MRI measurements, and ≥2 follow-up serum creatinine were reviewed. 1.5T, T2 -weighted single-shot fast spin echo, T1 -weighted 3D spoiled gradient echo (liver accelerated volume acquisition) and 2D cine velocity encoded gradient echo (phase contrast MRA). Ht-TKV, renal blood flow (RBF), number and fraction of renal and hepatic cysts, bright T1 hemorrhagic renal cysts, and liver and spleen volumes were independently assessed by three observers blinded to estimated glomerular filtration rate (eGFR) data. Linear mixed-effect models were applied to predict eGFR over time using MRI features at baseline adjusted for confounders. Validation was performed in 158 patients who had follow-up MRI using receiver operator characteristic, sensitivity, and specificity. Hemorrhagic cysts, fraction of renal and hepatic cysts, height-adjusted liver and spleen volumes were significant independent predictors of future eGFR (final prediction model R2 = 0.88 P < 0.05). The number of hemorrhagic cysts significantly improved the prediction compared to ht-TKV in predicting future eGFR (area under the curve [AUC] = 0.94, 95% confidence interval [CI]: 0.9-0.94 vs. R2 = 0.9, 95% CI: 0.85-0.9, P = 0.045). For baseline eGFR ≥60 ml/min/1.73m2 , sensitivity for predicting eGFR<45 ml/min/1.73m2 by ht-TKV alone was 29%. Sensitivity increased to 72% with all MRI variables in the model (P < 0.05 = 0.019), whereas specificity was unchanged, 100% vs. 99%. Combining multiple MR features including hemorrhagic renal cysts, renal cyst fraction, liver and spleen volume, hepatic cyst fraction, and renal blood flow enhanced sensitivity for predicting eGFR decline in ADPKD compared to the standard model including only ht-TKV. Level of Evidence 2 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2021;53:564-576.

Are Hemorrhagic Cysts Hyperintense Enough on T1-Weighted MRI to Be Distinguished From Renal Cell Carcinomas? A Retrospective Analysis of 204 Patients.

OBJECTIVE. The purpose of this study was to evaluate the utility of T1- and T2-weighted MRI signal-intensity ratios and signal-intensity SDs of renal lesions to determine the feasibility of distinguishing between simple cysts, hemorrhagic renal cysts, clear cell renal cell carcinoma (RCC), and papillary RCC. MATERIALS AND METHODS. Pathology records of 53 cases of papillary RCCs between 1 and 5 cm in size were included. Thirty-eight pathology-proven clear cell RCCs, 54 simple renal cysts seen on abdominal MRI, and 59 hemorrhagic renal cysts seen on abdominal MRI were identified. Lesion location and size, T1- and T2-weighted signal intensity, and corresponding SD values for each renal lesion and psoas muscle (from which lesion-to-muscle ratios were calculated) were collected. RESULTS. Analysis revealed a statistically significant difference (p < 0.001) in T1-weighted lesion-to-muscle signal-intensity ratios between simple cysts (mean ± standard error, 0.54 ± 0.05), clear cell RCCs (0.86 ± 0.06), papillary RCCs (1.17 ± 0.05), and hemorrhagic renal cysts (1.95 ± 0.04). The T2-weighted lesion-to-muscle signal-intensity ratios showed a statistically significant difference between all lesion types (p < 0.02) except between hemorrhagic renal cysts and papillary RCCs, where the difference approached significance (p = 0.075). ROC analysis showed an optimal cutoff of T1-weighted lesion-to-muscle signal-intensity ratio of 1.39 to differentiate hemorrhagic cysts (above this value) from RCCs (below this value). Corresponding sensitivity and specificity were 91.2% and 74.6%, respectively. CONCLUSION. T1-weighted lesion-to-muscle signal-intensity ratio is a useful measure to discriminate mildly hyperintense RCCs from more hyperintense hemorrhagic cysts when contrast enhancement is unavailable.

AN EXPERIENCE OF PARTIAL NEPHRECTOMY IN A PATIENT WITH VON WILLEBRAND DISEASE

A 28-year-old male visited a nearby hospital with chief complaint of bilateral back pain and fever. He was diagnosed with a right complex renal cyst (Bosniak classification, IIF) with a kidney stone and was referred to our hospital. We first suspected an incarcerated kidney stone and performed flexible transurethral lithotomy; however, his symptoms did not improve. Blood examination revealed prolonged APTT; subsequently, he was diagnosed with von Willebrand disease (VWD). Because he experienced pain due to the hemorrhagic renal cyst, we performed partial nephrectomy. Preoperatively, we supplemented the von Willebrand factor (VWF) based on the VWF activity in the patient. Although intraoperative bleeding was well controlled, he developed bleeding from pseudoaneurysms on the postoperative day (POD) 6. We immediately performed transarterial embolization along with VWF replenishment. VWF supplementation was discontinued on POD 14, and the patient was discharged on POD 23. Since then, he has not experienced a bleeding recurrence or pain. In patients with VWD, the perioperative administration of desmopressin or VWF is recommended. Although several reports showed that surgeries involving these treatments are safe, only three cases with VWD, including the present case where the patient underwent partial nephrectomy, have been reported. In the present case, postoperative bleeding occurred despite exhibiting adequate perioperative VWF activity. Thus, bleeding complications in patients with VWD undergoing partial nephrectomy must be considered and should be carefully followed up.

Wunderlich syndrome. Clinical and therapeutic aspects of a long-term experience

Wunderlich's syndrome is defined as a clinical manifestation secondary to sudden spontaneous rupture of renal parenchyma in the absence of injury, resulting in hemoretroperitoneum. This syndrome may occur in patients with benign or malignant neoplasm of the kidney, arterial venous fistulae, immunovasculitis and other phlogosis of the kidney. We present 19 cases of acute spontaneous hemoretroperitoneum or Wunderlich's syndrome diagnosed from 1996 to 2009, related to the following conditions: 7 renal carcinomas, 4 angiomyolipomas, 2 adrenal hemorrhages, 1 bleeding polycystic kidney, 2 hemorrhagic renal cysts and three cases of immunovasculitis. Overall, 6 patients were treated with acetylsalicylic acid and 4 with dicumarolics for cardiovascular disease, while 13 patients were suffering from hypertension? In 19 cases there was no mortality and the following treatment was performed: 11 nephrectomy, 4 partial nephrectomy, 2 adrenalectomy, 2 selective embolization of intrarenal branches as single treatment, while in three other cases, the embolization was carried out from a surgical procedure, conservative (partial nephrectomy) in one case, ablative (nephrectomy) in two other cases. The spontaneous hemoretroperitoneum is a rare syndrome associated with acute kidney disease often unknown to the patient and only in selected cases with small hematoma; it is possible to perform arteriography with selective embolization of branches avoiding renal access surgery. So far, it is unknown to which extent anti-platelet and anticoagulant drug treatment contributes to this syndrome but, in our experience, they have increased the morbidity of the clinical condition.

Atipična renalna cista koja imitira bubrežni karcinom - prikaz slučaja

Kidney atypical cystsclassified as Bosniak III or IV are suspicious of malignancy lesions. It is difficult in some cases to establish a right diagnosis based on radiological examinations and suggest appropriate therapeutic approach. A case of complicated hemorrhagic renal cyst in a 73 - years-old men is reported. The patient was admitted to our hospital for further evaluation of non specific abdominal and back pain and chronic urinary infections. Sonography showed a bilateral large cyst some of them with dense content. CT and MRI pointed to signs of malignancy in one cyst of left kidney, CT revealed Bosniak II F but MRI revealed suspicious malignant lesion. The presence of a malignant tumor in the cyst wall was suspected and nephrectomy was performed.Pathohistological examination showed evidence of inflamedhemorrhagic renal cystwithout malignancy. Atypical cysts can match a complicated cyst (infection, bleeding) or a cystic tumor. Radiological examination is often not enough for a clear differentiation false negative biopsy results in this group are commonand it may be necessary to perform a surgical treatment for an accurate diagnosis.

MP39-05 TRANSPOSON MUTAGENESIS DRIVES RENAL CYST FORMATION IN VIVO WHEN COMBINED WITH C-MET HYPERACTIVATION: IMPLICATIONS FOR ACQUIRED RENAL CYSTIC DISEASE

You have accessJournal of UrologyKidney Cancer: Basic Research & Pathophysiology I1 Apr 2017MP39-05 TRANSPOSON MUTAGENESIS DRIVES RENAL CYST FORMATION IN VIVO WHEN COMBINED WITH C-MET HYPERACTIVATION: IMPLICATIONS FOR ACQUIRED RENAL CYSTIC DISEASE Jason Scovell, Juan Hernandez, Adam Hollander, and Richard Link Jason ScovellJason Scovell More articles by this author , Juan HernandezJuan Hernandez More articles by this author , Adam HollanderAdam Hollander More articles by this author , and Richard LinkRichard Link More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.1179AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Acquired renal cystic disease (ARCD) imparts a high risk for renal cell carcinoma (8%) in patients with end-stage renal disease. The molecular mechanism of cyst formation in ARCD remains unknown, although increased hepatocyte growth factor / C-MET signaling have been implicated in cyst formation. To explore molecular mechanisms of renal cyst development relevant to ARCD, we developed a murine model system based on tissue-selectable C-Met activation and transposon-mediated mutagenesis. METHODS To allow conditional activation of C-Met signaling, we engineered a tandem duplicated and mutated human C-MET coding sequence. Cre recombinase catalyzes exchange of the wild type C-Met locus with a constitutively active variant (M1248T). C-met+/M1248T mice were crossed with mice carrying the mutagenic Sleeping Beauty (Onc2) transposable element activated by a cre-dependent transposase (trpase). Localization to the renal epithelium was achieved by ggt-cre. Mice with activated C-Met and transposon mutagenesis (1: c-met+/M1248T; Onc2+/-, trpase+/-; ggt-cre+/-) were compared to mice with activated C-Met (2: c-met+/M1248T; ggt-cre+/-) or activated transposon mutagenesis (3: Onc2+/-, trpase+/-; ggt-cre+/-) alone. Mice were serial imaged by ultrasound and MRI. All kidneys were then examined grossly and histologically at necropsy after aging. RESULTS All mice (N=5) with both C-Met hyperactivation and transposon activity (1) developed large renal cysts by 6 months. No mice with only C-Met hyper-activation (2; N=10) or transposon activity (3; N=10) developed cysts by 6 months. Histological analysis demonstrated fluid filled and hemorrhagic renal cysts without evidence for malignancy. CONCLUSIONS C-Met hyperactivation is insufficient to drive renal cyst formation in isolation. Combining M1248T with transposon mutagenesis drove renal cyst formation with 100% penetrance. By mapping transposon insertion sites in cyst-lining epithelial cells in this model, we can now begin to isolate these interacting genes, which may improve our understanding of the molecular mechanisms underlying ARCD. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e494-e495 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Jason Scovell More articles by this author Juan Hernandez More articles by this author Adam Hollander More articles by this author Richard Link More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Visual Assessment of the Intensity and Pattern of T1 Hyperintensity on MRI to Differentiate Hemorrhagic Renal Cysts From Renal Cell Carcinoma.

The purpose of this study was to apply a visual assessment of the intensity and pattern of T1 hyperintensity at MRI to differentiate hemorrhagic renal cysts from renal cell carcinoma (RCC). A total of 144 T1-hyperintense renal lesions (62 cysts, all showing no enhancement on subtracted contrast-enhanced images and either 2-year stability or unenhanced CT density > 70 HU, and 82 histologically confirmed RCCs) in 144 patients were included. Two radiologists independently characterized qualitative features of the T1 hyperintensity in each lesion on unenhanced T1-weighted images. An additional radiologist placed ROIs to measure lesions' T1 signal intensity normalized to that of the psoas muscle. Chi-square and unpaired t tests were performed to compare the pattern of T1 hyperintensity between groups. The T1 hyperintensity was considered marked in 62.9% of cysts and 17.1% of RCCs for reader 1 and in 46.8% of cysts and 8.5% of RCCs for reader 2 (p < 0.001). The T1 hyperintensity exhibited a diffusely homogeneous distribution in 88.7% of cysts and 7.3% of RCCs for reader 1 and in 72.6% of cysts and 4.9% of RCCs for reader 2 (p < 0.001). The combination of both diffusely homogeneous distribution and marked degree of T1 hyperintensity achieved sensitivities of 40.3-56.5%, specificities of 97.6-98.8%, and accuracies of 73.6-79.9% for the diagnosis of T1-hyperintense cysts. The two cases of RCC exhibiting this imaging pattern for at least one reader were both papillary RCCs. Normalized signal intensity was 2.39 ± 0.99 in T1-hyperintense cysts versus 2.12 ± 0.84 in T1-hyperintense RCCs (p = 0.088). Diffuse T1 hyperintensity, particularly when marked, strongly indicates a hemorrhagic cyst rather than an RCC. Deferral of follow-up imaging may be considered when this imaging appearance is encountered at unenhanced MRI.

Tüberoz Skleroz Kompleksi ve Otozomal Dominant Polikistik Böbrek Hastalığı Birlikteliği: Bir Olgu Sunumu

A 22 year-old-male was admitted with macroscopic hematuria. He had a diagnosis of tuberous sclerosis complex (TSC). On physical examination, angiofibromas were observed in the nasolabial folds and hypomelanotic macules were present on the lower extremities. Abdominal computed tomography revealed that both kidneys were extremely enlarged with numerous cysts resembling autosomal dominant polycystic kidney disease (ADPKD). The hematuria was considered to be caused by hemorrhagic renal cysts or undetected angiomyolipomas. At follow-up, end-stage renal disease developed and hemodialysis was started. TSC is an autosomal dominant disease in which hamartomas and cysts may develop in the brain, lungs, kidneys, heart and skin. TSC is caused by inactivating mutations in TSC1 on chromosome 9q32-q34 or TSC2 on chromosome 16p13, adjacent to the PKD1 gene. Large deletions involving both PKD1 and TSC2 may lead to the PKD1/TSC2 contiguous gene deletion syndrome that may cause an overlap syndrome having the clinical features of both TSC and ADPKD, as in this case. KEy wORdS: Tuberous sclerosis complex, Autosomal dominant polycystic kidney disease, Hematuria, Epilepsy, Angiofibromas, Hypomelanotic macule GiriS Tuberoz skleroz kompleksi (TSK) otozomal dominanat gecis gosteren santral sinir sistemi, deri ve bobrekleri tutan norokutanoz bir hastaliktir. 1880 yilinda Desire-Magloire Bourneville tarafindan tanimlanmistir. Mental retardasyon, epileptik nobetler ve sebase adenomlar tuberosklerozun klasik klinik triadini olusturur. Deri lezyonlari adenoma sebaseum, periungal fibromlar, bag dokusu nevusleri ve hipomelanotik makuller seklindedir.

Subtraction images: A really helpful tool in non-vascular MRI

BackgroundSubtraction imaging is a technique whereby an unenhanced T1-weighted sequence is digitally subtracted from the identical sequence performed after gadolinium administration. Aim of the workThis study will highlight the role of subtraction imaging for non-vascular MRI applications. Subjects and methodsThe study included 40 patients presenting with lesions in different parts of the body, that are initially hyperintense on T1W sequences.We used post-processing software (Osirix) to digitally subtract the pre-enhancement from the post enhancement sequences. ResultsBased on subtraction imaging findings 5 patients were diagnosed with intraocular melanomas, two patients were diagnosed with hemorrhagic cysts in the masseter muscle, two patients were diagnosed with hemorrhagic cysts in the parotid gland, two patients were diagnosed with dysplastic hepatic nodules, 5 patients were diagnosed with post-ablation necrosis following hepatocellular carcinoma (HCC) treatment, two patients showed recurrent HCC after chemoembolisation, 3 patients showed chemoembolised HCC without recurrence, 4 patients showed intraluminal gall bladder sludge, 4 patients showed hemorrhagic renal cysts, one patient showed solid papillary neoplasm of the pancreas, 6 patients showed chocolate ovarian cysts, two patient showed ovarian cystadenoma and two patients showed ovarian cystadenocarcinoma. ConclusionSubtraction MRI is very helpful tool in non-vascular MRI applications.

Nephrogenic Adenoma

Nephrogenic adenoma of the urinary bladder, where they present most frequently, are typically confined to the lamina propria but can on occasion focally involve the superficial muscularis propria. Less commonly, nephrogenic adenoma involves the renal pelvis and ureter where again they almost always only involve the lamina propria. We identified 3 consult cases in which tubules of nephrogenic adenoma extensively involved the muscularis propria and focally infiltrated the perinephric adipose tissue, for which the contributing pathologists considered the diagnosis of adenocarcinoma. In 1 case, that of a 71-year-old man, the lesion was associated with a hemorrhagic renal cyst (3.0 cm) and a spontaneous retroperitoneal bleed (6.0 cm) of unknown origin. In the second case, that of a 73-year-old woman, 2 foci (2.2, 1.6 cm) were present in the renal pelvis. They developed after biopsy of a low-grade noninvasive papillary urothelial carcinoma in the same site complicated by perforation. The third case was that of a 20-year-old woman with ureteropelvic junction obstruction and severe hydronephrosis associated with renal calculi. In all cases, the lesions were positive for CK7 and PAX8. These 3 cases report the novel finding that nephrogenic adenoma can occasionally have a deep infiltrative pattern into perinephric adipose tissue, possibly as a result of either biopsy-associated perforation or extensive disruption due to hemorrhage or mechanical obstruction. Awareness of this worrisome infiltration pattern, although rare, can prevent a misdiagnosis of an infiltrating carcinoma.

Selective Renal Parenchymal Clamping in Retroperitoneal Partial Nephrectomy

Herein, we report our experience with retroperitoneoscopic partial nephrectomy (RPN) without hilar occlusion by the use of a laparoscopic clamp to induce selective regional ischemia. A 48-year-old woman was referred for a left upper polar renal mass, which was suspected to be malignant. The contralateral kidney revealed severe atrophy, and she was scheduled to undergo RPN using a laparoscopic clamp to induce selective regional ischemia. At first, the kidney is fully mobilized within the retroperitoneal space. Thereafter, the laparoscopic clamp is applied directly to the kidney, about 1 cm below the resection line. When closed, the renal parenchyma is compressed, so that blood supply to the tumor is interrupted. The preserved portion of the kidney is perfused normally, and it is possible to remove the tumor in a bloodless field without involving warm ischemia. Renal hilar clamping was avoided, with minimal estimated blood loss. There was no perioperative complication, and the final pathology revealed a hemorrhagic renal cyst. The radioisotope absorption of the enucleated kidney was well maintained, except for the marginal area of the enucleated site. The renogram pattern was found to be equivocal when compared with the preoperative renogram. Regional renal parenchymal clamping during RPN can be safely and effectively used to create a bloodless operative field. Moreover, our preliminary experience demonstrates that this technique facilitates maximal nephron-sparing surgery for patients with an anatomically or functionally solitary kidney, without involving warm ischemia.

Wunderlich Syndrome. Clinical and Therapeutic Aspects of a Long-Term Experience

Introduction Wunderlich's syndrome is defined as a clinical manifestation secondary to sudden spontaneous rupture of renal parenchyma in the absence of injury, resulting in hemoretroperitoneum. This syndrome may occur in patients with benign or malignant neoplasm of the kidney, arterial venous fistulae, immunovasculitis and other phlogosis of the kidney. Materials and Methods We present 19 cases of acute spontaneous hemoretroperitoneum or Wunderlich's syndrome diagnosed from 1996 to 2009, related to the following conditions: 7 renal carcinomas, 4 angiomyolipomas, 2 adrenal hemorrhages, 1 bleeding polycystic kidney, 2 hemorrhagic renal cysts and three cases of immunovasculitis. Overall, 6 patients were treated with acetylsalicylic acid and 4 with dicumarolics for cardiovascular disease, while 13 patients were suffering from hypertension Results In 19 cases there was no mortality and the following treatment was performed: 11 nephrectomy, 4 partial nephrectomy, 2 adrenalectomy, 2 selective embolization of intrarenal branches as single treatment, while in three other cases, the embolization was carried out from a surgical procedure, conservative (partial nephrectomy) in one case, ablative (nephrectomy) in two other cases. Conclusions The spontaneous hemoretroperitoneum is a rare syndrome associated with acute kidney disease often unknown to the patient and only in selected cases with small hematoma; it is possible to perform arteriography with selective embolization of branches avoiding renal access surgery. So far, it is unknown to which extent anti-platelet and anticoagulant drug treatment contributes to this syndrome but, in our experience, they have increased the morbidity of the clinical condition.

Spontaneous Perinephric Hemorrhage from a Hemorrhagic Renal Cyst

Spontaneous Perinephric Hemorrhage from a Hemorrhagic Renal Cyst

Evaluation of imaging-guided fine-needle percutaneous biopsy of renal masses

To evaluate the utility of imaging-guided fine-needle percutaneous biopsy of renal masses, we conducted a prospective analysis of our imaging-guided procedures from January 1999 to February 2003. We performed 54 percutaneous core biopsies in 46 patients. Fluoro-computed tomography and ultrasound guidance were respectively used in 48 and six cases. One to four specimens were obtained by using an 18-gauge automated coaxial biopsy system. We reviewed the patients medical records, pathology results, and imaging studies. Core biopsy results were compared with surgical pathology (n=27) or clinical follow-up (n=19). All biopsies provided sufficient material for analysis. The mean tumor size was 33 mm. Biopsy findings were positive for malignancy in 31 cases; histologic diagnoses included renal cell carcinoma (n=23), transitional cell carcinoma (n=5), and metastasis (n=3). Biopsy revealed 15 benign diagnoses: oncocytoma (n=6), hemorrhagic renal cyst (n=3), chronic nephritis (n=3), angiomyolipoma (n=2), and mycotic renal abscess (n=1). The average follow-up period for patients with benign diagnoses was 16 months. Biopsy results showed normal renal parenchyma in eight of 54 procedures, all of which had recuperated by subsequent biopsies. No immediate complications occurred after the procedures. Imaging-guided percutaneous core biopsy is a safe and accurate method for the evaluation of renal masses.

Evaluation of imaging-guided fine-needle percutaneous biopsy of renal masses

To evaluate the utility of imaging-guided fine-needle percutaneous biopsy of renal masses, we conducted a prospective analysis of our imaging-guided procedures from January 1999 to February 2003. We performed 54 percutaneous core biopsies in 46 patients. Fluoro-computed tomography and ultrasound guidance were respectively used in 48 and six cases. One to four specimens were obtained by using an 18-gauge automated coaxial biopsy system. We reviewed the patients medical records, pathology results, and imaging studies. Core biopsy results were compared with surgical pathology (n=27) or clinical follow-up (n=19). All biopsies provided sufficient material for analysis. The mean tumor size was 33 mm. Biopsy findings were positive for malignancy in 31 cases; histologic diagnoses included renal cell carcinoma (n=23), transitional cell carcinoma (n=5), and metastasis (n=3). Biopsy revealed 15 benign diagnoses: oncocytoma (n=6), hemorrhagic renal cyst (n=3), chronic nephritis (n=3), angiomyolipoma (n=2), and mycotic renal abscess (n=1). The average follow-up period for patients with benign diagnoses was 16 months. Biopsy results showed normal renal parenchyma in eight of 54 procedures, all of which had recuperated by subsequent biopsies. No immediate complications occurred after the procedures. Imaging-guided percutaneous core biopsy is a safe and accurate method for the evaluation of renal masses.

Spontaneous retroperitoneal hemorrhage secondary to subcapsular renal hematoma: MRI findings

Spontaneous retroperitoneal hemorrhage is a rare intraabdominal bleeding. In this report we present a case of a nontraumatic retroperitoneal hemorrhage secondary to spontaneous subcapsular renal hematoma. A 54-year-old patient who was under warfarin therapy, developed subcapsular right renal hematoma. Subcapsular and retroperitoneal hemorrhage were low signal on T1- and T2-weighted images consistent with acute stage of blood. The source of subcapsular hematoma was shown to be the rupture of hemorrhagic renal cyst on MRI. Extension of hemorrhage into the retroperitoneal space anterior to right psoas muscle was also successfully shown on MRI. Patient underwent nephrectomy and retroperitoneal blood was evacuated.

IDIOPATHIC RETROPERITONEAL HEMATOMA MIMICKING CYSTIC TUMOR ASSOCIATED WITH HEMORRHAGIC RENAL CYST

A 54-year-old woman was admitted to the hospital for evaluation of a retroperitoneal cystic mass detected incidentally during a complete followup physical examination for hypertension. CT revealed a 3 3 3 cm. cystic tumor between the inferior vena cava and abdominal aorta, and a 1 3 1 cm. enhanced mass in the left kidney (fig. 1). Magnetic resonance imaging showed that the inferior vena cava and abdominal aorta were deviated laterally by the mass in front of the vertebra, and a high density tumor in the left kidney was found (fig. 2). Angiography demonstrated no feeding arteries to the retroperitoneal mass or ruptured vessels. Preoperative diagnosis was cystic retroperitoneal and left renal tumors. To rule out lymphocele and retroperitoneal hematoma resection of the retroperitoneal mass and left partial nephrectomy were performed. The retroperitoneal mass was adherent to the inferior vena cava, abdominal aorta and vertebra, and had more capsular vessels than expected. Fluid collection of the retroperitoneal mass and left renal mass revealed an old hematoma and hematoma clot, respectively. Histologically, there were features of fibrous scar with fibrin and monocyte infiltration, while the left renal mass had no evidence of malignancy. Final diagnosis was idiopathic retroperitoneal hematoma and benign hemorrhagic renal cyst. No history of gastrointestinal upset, surgery or trauma was noted, and the cause of retroperitoneal hematoma and origin of the bleeding could not be identified. Convalescence was uneventful, although hypertension did not subside. The patient was well without evidence of disease recurrence at 1-year followup.

RENAL ONCOCYTOMA MIMICKING HEMORRHAGIC RENAL CYST

A case of oncocytoma, the radiological findings of which resembled a hemorrhagic renal cyst, is reported. Cyst fluid analysis demonstrated extremely high levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). Preoperatively the lesion was regarded a malignant cyst, and radical nephrectomy was performed. Pathological diagnosis was renal oncocytoma with cystic degeneration. Although cystic change occasionally has been mentioned in oncocytoma, a high level of CEA and CA 19-9 in the cyst fluid of the cystic oncocytoma have not been reported. We discuss the variant forms of oncocytoma and tumor markers in the cyst fluid.