Perinephric Tissue Research Articles

Emphysematous Pyelonephritis in Two Cases at Two Different Stages: Early and Late

Emphysematous pyelonephritis (EPN) has been defined as a necrotizing infection of the renal parenchyma and its surrounding areas that result in the presence of gas in the renal parenchyma, collecting system or perinephric tissue. The final diagnosis mostly depends on the radiological findings since clinical and biochemical findings of the EPN can be different from case to case. The diseases can be seen not only in diabetic patients but also occasionally in patients without diabetes mellitus with obstruction of the the urinary system. In this article, we discussed the EPN based on two patients at the two different stages, late and early, respectively. J Med Cases. 2014;5(6):357-361 doi: http://dx.doi.org/10.14740/jmc1799w Normal 0 21 false false false TR X-NONE X-NONE

Handling and staging of renal tumors: an update for a practising pathologist

The International Society of Urologie Pathology 2012 Conference on renal cancer discussed the staging and specimen handling of renal tumors. For specimen handling, the initial cut should be made along the long axis. Renal tumors should be sampled 1 block/cm with a minimum of 3 blocks. The length of a renal vein/caval thrombus should not be part of main tumor measurement. In cases with multiple tumors, sampling should include a minimum of 5 largest tumors. Perinephric fat invasion should be determined by examining multiple perpendicular sections of the tumor/perinephric fat interface and by sampling areas suspicious for invasion. Perinephric fat invasion was defined as either the tumor touching the fat or extending as irregular tongues into the perinephric tissue, with or without desmoplasia. Renal sinus invasion is present when the tumor is in direct contact with the sinus fat or the loose connective tissue of the sinus, clearly beyond the renal parenchyma, or if any endothelium-lined space is involved within the renal sinus, regardless of the size. When invasion of the sinus is uncertain, at least 3 blocks of tumor-renal sinus interface should be submitted. If invasion is grossly evident, or obviously not present, only 1 block is needed.

A comparative histological, immunohistochemical, and biochemical study of the effect of green tea extracts or chromium picolinate administration on the white visceral adipose tissue and liver in albino rats fed on high-fat diet

Background Obesity has become a major health problem, as a growing proportion of the population worldwide is overweight. The coincidence of obesity, insulin resistance, hypertension, dyslipidemia, and hepatic steatosis is commonly referred to as the ‘metabolic syndrome’. The investigation of the antiobesity properties of food components is a popular field of research and one of these natural agents of interest is green tea extract (GTE). Nevertheless, chromium picolinate (CP) is also postulated to have an effect on the body fat composition. Objective The present study aimed to assess the changes in the visceral white adipose tissue and the liver of adult male albino rats that are fed on high-fat diet (HFD) following administration of GTE or CP supplements histologically, immunohistochemically, and biochemically. Materials and methods A total of 60 adult male albino rats (120–150g) were randomly assigned into four groups. Group I (the control group) included 30 rats and were subdivided into three equal subgroups (Ia, Ib, Ic); all were fed on standard rat chow. Groups Ib and Ic were given GTE and CP, respectively, orally through an orogastric tube. Group II included 10 rats that were allowed a free access to HFD. Group III (the GTE and HFD group) included 10 rats that received GTE orally (200 mg/kg body weight/day) in conjunction with HFD. Group IV (the CP and HFD group) included 10 rats that received CP orally (80 μg/kg body weight/day) in conjunction with HFD. The experiment continued for 3 months. Perinephric white adipose tissue (PWAT) and liver specimens were dissected from all rats at the end of the experiment for histological and immunohistochemical examination. Blood samples were taken for estimation of fasting blood glucose (FBG) and fasting blood insulin (FBI) levels. Results Histologically, groups Ib and Ic revealed almost the control pattern of the liver and PWAT similar to group Ia. Group II showed focal areas of cellular infiltration and congestion of the blood vessels of the liver sections. Most hepatocytes appeared swollen with cytoplasmic vacuolation. PWAT revealed a marked increase in the amount and size of the adipocytes. Groups III and IV revealed almost the control pattern of the liver except for few areas of cellular infiltrations in group IV. Groups III and IV showed a marked decrease in the amount of PWAT, which was more remarkable in group IV. Decrease in the size of many adipocytes was more manifested in group IV. Immunohistochemically, increased expression of insulin receptors in the adipocytes of PWAT and to a lesser extent in the hepatocytes of group III was noticed. Group IV showed more noticeable increased expression of insulin receptors compared with group III. Biochemically, FBI in the obesity group was higher as compared with the control group. Groups III and IV revealed a significant decrease in the FBI level. Fasting blood glucose level showed significant increase in group II only. Conclusion Supplementation with either GTE or CP may be useful as antiobesity agents and can be used to prevent the impact of obesity on the liver and to improve insulin resistance.

Renal carcinomas associated with Xp11.2 translocations/TFE3 gene fusions: Findings on MRI and computed tomography imaging

To retrospectively analyze MRI and computed tomographic (CT) findings from renal carcinomas associated with Xp11.2 translocations/TFE3 gene fusions (Xp11-RCC). Institutional review board permission was obtained to review patient medical records, and the requirement for informed consent was waved . The clinical and MRI/CT features of five cases with Xp11-RCC that were confirmed by pathology were analyzed retrospectively. The image characteristics included the lesion location and size, contribution of cystic and solid components, intratumoral necrosis or hemorrhage, invasion of perinephric tissue and renal sinus, lymphadenopathy, major venous or arterial vascular invasion, pattern of the tumor growth, intratumor calcification and lipids, homogeneity of SI on T2-weighted images, attenuation and SI of the mass with respect to the normal renal cortex on precontrast and contrasted CT/MRI images, tumor SIs, tumor attenuations and tumor-to-cortex indices, homogeneity of enhancement on the contrasted images. The mean age was 32 years (range, 15-47 years). Most patients (4/5) were women. All tumors showed a cortical location. The average tumor size was 9 cm (range, 4-18 cm). Four tumors comprised a predominantly solid lesion with focal necrosis, and one tumor comprised a solid lesion with significant necrosis. All tumors showed intertumor hemorrhage, infiltrative growth and invasion of the perirenal adipose/renal sinus. Four cases showed retroperitoneal lymphadenopathy, of which one case showed simultaneous mediastinal and supraclavicular lymphadenopathy. All tumors from four cases showed mild hyperintensity on T1-weighted MRI images, and three tumors showed hypointensity on T2-weighted MRI images relative to the renal cortex except for 1 tumor that showed significant hemorrhage and a relative hyperintensity. For 3 cases who were imaged with CT, two tumors imaged using nonenhanced CT images showed mild hyperdensity relative to the renal cortex. Calcification was noted in all three tumors. All tumors showed mild, persistent enhancement. Typical Xp11-RCC manifests as an advanced, solid renal mass with mild persistent enhancement, a prevalence of intertumor hemorrhage/calcification, and a cortical epicenter location. The predilection for children and young adults is a useful clinical feature when confirming a diagnosis of Xp11-RCC.

Handling and Staging of Renal Cell Carcinoma

The International Society of Urologic Pathology 2012 Consensus Conference on renal cancer, through working group 3, focused on the issues of staging and specimen handling of renal tumors. The conference was preceded by an online survey of the International Society of Urologic Pathology members, and the results of this were used to inform the focus of conference discussion. On formal voting a ≥65% majority was considered a consensus agreement. For specimen handling it was agreed that with radical nephrectomy specimens the initial cut should be made along the long axis and that both radical and partial nephrectomy specimens should be inked. It was recommended that sampling of renal tumors should follow a general guideline of sampling 1 block/cm with a minimum of 3 blocks (subject to modification as needed in individual cases). When measuring a renal tumor, the length of a renal vein/caval thrombus should not be part of the measurement of the main tumor mass. In cases with multiple tumors, sampling should include at a minimum the 5 largest tumors. There was a consensus that perinephric fat invasion should be determined by examining multiple perpendicular sections of the tumor/perinephric fat interface and by sampling areas suspicious for invasion. Perinephric fat invasion was defined as either the tumor touching the fat or extending as irregular tongues into the perinephric tissue, with or without desmoplasia. It was agreed upon that renal sinus invasion is present when the tumor is in direct contact with the sinus fat or the loose connective tissue of the sinus, clearly beyond the renal parenchyma, or if there is involvement of any endothelium-lined spaces within the renal sinus, regardless of the size. When invasion of the renal sinus is uncertain, it was recommended that at least 3 blocks of the tumor-renal sinus interface should be submitted. If invasion is grossly evident, or obviously not present (small peripheral tumor), it was agreed that only 1 block was needed to confirm the gross impression. Other recommendations were that the renal vein margin be considered positive only when there is adherent tumor visible microscopically at the actual margin. When a specimen is submitted separately as "caval thrombus," the recommended sampling strategy is to take 2 or more sections to look for the adherent caval wall tissue. It was also recommended that uninvolved renal parenchyma be sampled by including normal parenchyma with tumor and normal parenchyma distant from the tumor. There was consensus that radical nephrectomy specimens should be examined for the purpose of identifying lymph nodes by dissection/palpation of the fat in the hilar area only; however, it was acknowledged that lymph nodes are found in <10% of radical nephrectomy specimens.

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.

Emphysematous pyelonephritis caused by Candida species: first case in the English literature

Emphysematous pyelonephritis (EPN) is an acute severe necrotizing infection of the renal parenchyma and its surrounding tissues that results in the presence of gas in the renal parenchyma, collecting system or perinephric tissue. Our case was a 46-year-old diabetic woman who was referred to us from the emergency department. This is the first case of emphysematous pyelonephritis caused by Candida species in the English literature.

Extensive emphysematous pyelonephritis leading to renal destruction

Emphysematous pyelonephritis (EPN) is a severe necrotizing infection of the kidney characterized by the presence of gas in the renal parenchyma, collecting system or perinephric tissues. It can be life-threatening if not recognized and treated promptly. We report the case of a 56-year-old woman, on treatment for diabetes mellitus, who presented with left-sided flank pain and fever. Computerized tomography revealed EPN with extensive destruction of the left kidney. Intravenous antibiotics were administered and left nephrectomy was performed. The postoperative course was uncomplicated, but during 4 months follow-up the patient's renal function rapidly deteriorated. This case report emphasizes the need for appropriate management of EPN.

Emphysematous pyelonephritis: Presenting as diabetic ketoacidosis

Sir, Patients with diabetic ketoacidosis (DKA) usually have poor glycemic control for weeks to months before their presentation. It is necessary to rule out all the potential precipitating causes (most common being infections, especially pneumonia or urinary tract infection) for DKA during the management.[1] We report a 55-year-old female patient presenting with complaints of fever of 1 week duration. Fever was of high grade, intermittent, and was associated with chills and rigors. She was having breathlessness for 2 days before the presentation. Past history revealed that she was hypertensive and diabetic since 18 years; there were prior admissions with similar complaints, and she was diagnosed and treated for DKA. On examination, she was conscious, oriented, pale, febrile, tachypneic, dehydrated, and was having bilateral pitting pedal edema. Vitals showed tachycardia and hypotension. Systemic examination revealed bilateral wheeze, basal crepitations, and tenderness over the left loin. Investigations showed reduced hemoglobin (8 g/dL) and elevated total count (TC; 19,600/mm3) with polymorph predominance (90%). She had high blood glucose and poor glycemic control in the past 6 months (HbA1c 9.0 gm %). Her renal function tests and liver function tests were normal. Urine analysis showed that urine was positive for ketone bodies and active deposits (18–20 pus cells per high-power field). Arterial blood gas analysis showed high anion gap metabolic acidosis with inadequate respiratory compensation. She was diagnosed with DKA and possible sepsis. Blood and urine cultures were drawn and patient was treated with empirical antibiotics. DKA was treated with intravenous (IV) infusion of human insulin, fluid resuscitation with IV normal saline, and potassium supplementation. Ultrasonogram abdomen and pelvis revealed fatty liver, mild splenomegaly and hyperechoic lesion in the lower pole of left kidney. Contrast-enhanced computed tomography (CECT) abdomen and pelvis revealed hypodense lesion in the lower pole of left kidney [star in Figure 1], with air pockets [white arrows, Figure 1] visible within the lesion and in the perinephric tissues. Lesion was seen extending beyond the Gerota's fascia [black arrow, Figure 1], with perinephric fat stranding. Both blood culture and urine culture showed Escherichia coli growth [colony forming units (CFU) 105 in urine cultures]. She was finally diagnosed with sepsis, emphysematous pyelonephritis (EPN) Class 3B, and DKA. She was treated with percutaneous drainage of perinephric necrotic material under ultrasonogram guidance and with appropriate antibiotics, and glycemic control was achieved by IV infusions of human insulin. She made an uneventful recovery with the above management and was discharged with instructions to continue subcutaneous insulin injections for glycemic control. Figure 1 Contrast-enhanced computed tomography (CECT) abdomen and pelvis revealed hypodense lesion in the lower pole of left kidney (star in a), with air pockets (white arrows in b and c) visible within the lesion and in the perinephric tissues. Lesion was seen ... EPN is a severe necrotizing infection of the renal parenchyma, with gas formation within the collecting system, renal parenchyma, and/or perirenal tissues, seen usually in diabetic patients.[2] The first case of pneumaturia was reported in 1898; since then, approximately 200 cases have been reported. The commonly isolated organisms are E. coli (66%), Klebsiella (26%), Proteus, Pseudomonas, and Streptococcus; rarely, Candida and clostridium are also seen. Mixed organisms are seen in 10% of cases. The infection has a fulminating course and can be fatal. The factors that predispose are uncontrolled diabetes, high levels of glycosylated hemoglobin, and impaired host immunity.[3] The mean age of presentation is 55 years, and it is six times more common in diabetics and females. Obstruction is the main cause of EPN in non-diabetics. Staging of renal parenchymal gas is made radiologically, and is useful for decision making and prognostication.[4]

Emphysematous Pyelonephritis Caused by Candida Parapsilosis: An Unknown Etiological Agent

Emphysematous pyelonephritis (EPN) a rare complication commonly seen in diabetic patients is a necrotising gas producing infection of the renal parenchyma and perinephric tissue predominantly caused by uropathogenic bacteria. Fungi have been rarely reported as the etiological agents, isolated from blood and/ or urine culture. We report a case of EPN caused by a rare etiological agent. A 60 year old diabetic female with no previous history of hospitalization presented to us with a short history of febrile illness associated with abdominal pain. Investigations revealed unilateral EPN “Wan type 1”. Patient was treated with systemic antifungal therapy as per culture sensitivity and it alone proved to be an effective treatment of this clinically difficult condition. Patient was discharged in a satisfactory clinical condition. A rare etiology should always be kept in mind while evaluating a case of EPN.

Squamous cell carcinoma of the renal pelvis

Primary squamous cell carcinoma (SCC) of the renal pelvis is rare because SCC represents only 0.5% to 0.8% of malignant renal tumors. Chronic irritation, inflammation, and infection induce squamous metaplasia of the renal collecting system, which may progress to dysplasia and carcinoma in most of affected individuals. Nephrolithiasis, especially formation of staghorn calculi, is the most common risk factor for SCC, which usually occurs in older adults (age 50-70 years) with no sex predilection. Clinical features include flank or abdominal mass, weight loss, hematuria, or paraneoplastic syndromes, such as hypercalcemia. Radiologically, SCC of the renal pelvis may appear as a solid mass, hydronephrosis, or calcifications. The radiologic differential diagnosis includes primary and secondary renal neoplasms and xanthogranulomatous pyelonephritis. Squamous cell carcinomas of the renal pelvis are usually large, necrotic, and ulcerated, with gross invasion of the renal parenchyma and perinephric soft tissue. Most SCCs of the renal pelvis are moderately or poorly differentiated and typically present at an advanced stage. Surgical resection and adjuvant chemoradiotherapy are rarely curative. The prognosis is dismal with a 5-year survival rate of less than 10%.

Small cell carcinoma of the kidney: a clinicopathologic study of 14 cases

Small cell carcinoma of the kidney is distinctively rare. We searched pathology files in 2 institutions and found 14 cases of renal small cell carcinoma. The patients' mean age at diagnosis was 59 years (range, 22-75 years); 8 were women, and 6 were men. Patients usually presented with hematuria (n = 6) and abdominal pain (n = 5). The mean tumor size was 7.1 cm (range, 3.5-14.0 cm). The small cell carcinoma was pure in 9 cases and mixed with high-grade urothelial carcinoma in 5 cases. None was associated with any type of renal cell carcinoma. Tumor necrosis was present in all cases, and lymphovascular invasion was identified in 6 cases. The tumor invaded the perinephric adipose tissue in 13 cases and was confined to the kidney in only 1 case. Lymph node metastases were identified in all patients who underwent lymph node dissection (5/5). On immunostains, the small cell carcinoma cells were positive for pancytokeratin (11/12), chromogranin (6/9), and synaptophysin (8/9). Follow-up data were available for 13 patients, and 11 died of small cell carcinoma at a mean of 15 months (range, 4-31 months) after diagnosis. Of the 2 surviving patients, 1 was alive at 5 months after diagnosis, and the other, whose disease was confined to the kidney, was alive with no evidence of disease at 137 months. In summary, renal small cell carcinoma is a highly aggressive disease that often presents at an advanced stage with widespread metastases. Patients usually have a poor clinical outcome despite multimodal therapy. The frequent coexistence of small cell carcinoma with urothelial carcinoma suggests that renal small cell carcinomas may evolve from a preexisting urothelial carcinoma.

Anatomical site influences the differentiation of adipose‐derived stem cells for Schwann‐cell phenotype and function

Considerable attention has recently been given to adipose-derived stem cells (ASCs) as an important source for differentiation to Schwann cells in the treatment of peripheral nerve injury, with considerable clinical advantages over the use of mesenchymal stem cells derived from bone marrow or autologous Schwann cells. However, the relationship between adipose donor site and differentiated ASC phenotype and function is presently unknown. This work systematically studied the differentiation of ASCs harvested from three anatomical sites: (i) subcutaneous; (ii) perinephric; and (iii) epididymal adipose tissue. We show that ASC source is a major determining factor of immunophenotype, multilineage differentiation, Schwann-cell protein expression, and paracrine ability to stimulate neuronal growth. Upregulation of S100β, glial fibrillary acidic protein (GFAP), and p75NGFR was observed in differentiated ASCs from perinephric fat tissue, while only the expression of S100β or GFAP and p75NGFR was elevated in differentiated ASCs from subcutaneous or epididymal fat tissue. Although the co-culture of differentiated ASCs with NG108-15 neuronal cells demonstrated that ASCs from each source could stimulate neurite outgrowth and number, differentiated ASCs from subcutaneous and perinephric fat versus epididymal fat were most effective, which was attributed to high-brain-derived neurotropic factor/nerve growth factor and low-neurotrophin-3 levels. Thus, ASCs can be obtained from different anatomical locations, and this determines Schwann-cell phenotype upon differentiation and extent of function. This work is therefore of relevance in local therapeutic delivery of ASCs for the repair of peripheral nerve injury, but also in the broader context of ASC use in related stem-cell therapies.

Emphysematous pyelonephritis

Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? Emphysematous pyelonephritis (EPN) is a severe necrotizing infection of the renal parenchyma. The clinical course of EPN can be severe and life‐threatening if not recognized and treated promptly. Most of the information has been from case reports, a few large series have also been reported. Using an evidence‐based approach, this review describes the pathogenesis, classification, complications, and management of EPN.Emphysematous pyelonephritis (EPN) is an acute severe necrotizing infection of the renal parenchyma and its surrounding tissues that results in the presence of gas in the renal parenchyma, collecting system, or perinephric tissue. The cause for mortality in EPN is primarily due to septic complications. Up to 95% of the cases with EPN have underlying uncontrolled diabetes mellitus. The risk of developing EPN secondary to a urinary tract obstruction is about 25–40%. There are three classifications of EPN based on radiological findings. Acute renal failure, microscopic or macroscopic haematuria, severe proteinuria are other positive findings in EPN. Escherichia coli is the most common causative pathogen with the organism isolated on urine or pus cultures in nearly 70% of the reported cases.A plain radiograph shows an abnormal gas shadow in the renal bed raising the suspicion whereas an ultrasound scan or computed tomography (CT) will confirm the presence of intra‐renal gas thus supporting the diagnosis of EPN. Gas may extend beyond the site of inflammation to the sub capsular, perinephric and pararenal spaces. In some cases, gas was found to be extending into the scrotal sac and spermatic cord.Subsequent case studies have shown patients being successfully treated with PCD when used in addition to medical management, with significant reduction in the morality rates. PCD should be performed on patients who have localized areas of gas and functioning renal tissue is present. The treatment strategies include MM alone, PCD plus MM, MM plus emergency nephrectomy, and PCD plus MM plus emergency nephrectomy. In small proportion of patients managed with MM and PCD, subsequent nephrectomy will be required and in these patients the reported mortality is 6.6% Nephrectomy in patients with EPN can be simple, radical or laparoscopic.

Xanthogranulomatous Pyelonephritis in a male child with renal vein thrombus extending into the inferior vena cava: a Case Report

BackgroundWe present a case of Xanthogranulomatous pyelonephritis (XGPN) in a male child with renal vein thrombus extending into the inferior vena cava. This is a rare presentation. XGPN is a rare type of renal infection characterised by granulomatous inflammation with giant cells and foamy histiocytes. The peak incidence is in the sixth to seventh decade with a female predominance. XGPN is rare in children.Case presentationAn 11 year old male child presented with a history of high grade fever and chills, right flank pain and progressive pyuria for two months. He had a history of vesical calculus for which he was operated four years back. In our case, a subcapsular right nephrectomy was performed. The surgical specimens were formalin fixed and paraffin embedded. The sections were stained with routine Hematoxylin & Eosin stain. Grossly; the kidney was enlarged with adherent capsule and thickening of the perinephric tissue. The pelvicalyceal system was dilated and was filled with a cast of pus. Histological evaluation revealed diffuse necrosis of the renal parenchyma and perinephric fat. Neutrophils, plasma cells, sheets of foamy macrophages and occasional multinucleate giant cells were seen. The renal vein was partially occluded by an inflammatory thrombus with fibrin, platelets and mixed inflammatory cells. The thrombus was focally adherent to the vein wall with organization.ConclusionsThe clinical presentation and the macroscopic aspect, together with the histological pattern, the cytological characteristics addressed the diagnosis towards XGPN with a vena caval thrombus. Our case illustrates that the diagnosis of XGPN should be considered even in paediatric age group when renal vein and vena caval thrombi are present.

Clear cell renal cell carcinoma with focal renal angiomyoadenomatous tumor-like area

Recently, renal angiomyoadenomatous tumor (RAT) has been identified. However, there are no descriptions about clear cell renal cell carcinoma (RCC) with focal RAT-like features. A 33-year-old Japanese man was found to have a tumor in the left kidney. Macroscopically, the tumor extended into the perinephric fat tissue, and the cut surface showed the yellowish color. The histologic examination of the tumor consisted of 2 components of clear cell RCC and RAT-like area. The RAT-like area showed the admixture of epithelial cells with basophilic or clear cytoplasm and stromal component containing leiomyomatous stroma, fine capillary network, and pericytic network. Immunohistochemically, epithelial neoplastic cells in RAT-like area were diffusely positive for CD10 and RCC Ma. G-band karyotype showed the structural abnormality of chromosome 3 and both components of clear cell RCC and RAT-like area revealed the identical VHL gene mutation. Finally, pathologists should pay attention to the presence of clear cell RCC focally resembling RAT.

A 2-µm Continuous-Wave Laser System for Safe and High-Precision Dissection During NOTES Procedures

Lasers 2-microm in wavelength offer efficient tissue cutting with limited thermal damage in biological tissue. To evaluate the dissection capabilities of a 2-microm continuous-wave laser for NOTES procedures. We conducted 18 acute animal experiments. Group 1 (three animals): transcolonic access to the peritoneal cavity (15-W transcolonic laser puncture, balloon dilation over the laser probe). Group 2 (six animals): transcolonic access with needle-knife puncture and balloon dilation. Group 3 (three animals): transgastric access to the peritoneal cavity (similar technique as group 1) followed by laser-assisted dissection of the kidney. In one animal of group 3, a therapeutic target (hematoma) was created by percutaneous puncture of the kidney. Group 4 (six animals): transgastric access (similar to the technique of group 2). Translumenal access to the peritoneal cavity was achieved in 2-3 min in group 1 (significantly shorter than with the needle-knife-assisted technique, 4-5 min, p=0.02) and in 7-10 min in group 3 (compared to 6-17 min in group 4, p=0.88). In group 3, laser dissection of the parietal peritoneum and of perinephric connective tissue allowed access to the retroperitoneum with complete removal of a blood collection in the animal with puncture trauma. Laser dissection demonstrated good maneuverability, clean and rapid cutting, and excellent hemostasis. Peritoneoscopy and necropsy showed no damage of targeted tissue and surrounding organs. The 2-microm continuous-wave laser system showed promising capabilities for highly precise and safe dissection during NOTES procedures.

Primary Pancreatic Sinus Histiocytosis With Massive Lymphadenopathy (Rosai-Dorfman Disease): An Unusual Extranodal Manifestation Clinically Simulating Malignancy

Abstract Sinus histiocytosis with massive lymphadenopathy (SHML), also called Rosai-Dorfman disease, is a rare entity. Its etiology and pathogenesis are still essentially unclear. The histologic hallmark of this disease is proliferation of distinctive histiocytes within lymph node sinuses and in extranodal sites. Approximately 23% of patients with SHML, documented in the SHML Registry, presented with disease primarily in extranodal sites, and very few cases of SHML (<1%) involving the gastrointestinal system have been described in the literature. We report an unusual case of primary pancreatic SHML with infiltration of the process into peripancreatic, perinephric, and perisplenic adipose tissue, simulating malignancy.

Primary Pancreatic Sinus Histiocytosis With Massive Lymphadenopathy (Rosai-Dorfman Disease): An Unusual Extranodal Manifestation Clinically Simulating Malignancy

Abstract Sinus histiocytosis with massive lymphadenopathy (SHML), also called Rosai-Dorfman disease, is a rare entity. Its etiology and pathogenesis are still essentially unclear. The histologic hallmark of this disease is proliferation of distinctive histiocytes within lymph node sinuses and in extranodal sites. Approximately 23% of patients with SHML, documented in the SHML Registry, presented with disease primarily in extranodal sites, and very few cases of SHML (<1%) involving the gastrointestinal system have been described in the literature. We report an unusual case of primary pancreatic SHML with infiltration of the process into peripancreatic, perinephric, and perisplenic adipose tissue, simulating malignancy.

Pseudosarcomatous fibroblastic/myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma: a lesion mimicking well-differentiated liposarcoma

Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking well-differentiated liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in well-differentiated liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as well-differentiated liposarcoma.