Leiomyoma of the kidney: presentation of 4 new cases and the role of computerized tomography

Renal leiomyoma is a challenging diagnostic and therapeutic condition. It is clinically similar in presentation and radiographic appearance to its malignant counterpart, leiomyosarcoma. We review 30 cases of clinically diagnosed leiomyoma of the kidney from the literature, including 4 new cases with emphasis on the computerized tomography findings. Computerized tomography may locate a renal leiomyoma serendipitously in an asymptomatic patient. If the lesion is peripheral or in the parapelvic area and a plane can be seen between the tumor and kidney a capsular tumor, such as a leiomyoma of the kidney, might be considered in addition to the more common renal cell carcinoma. Renal leiomyomas have a variable radiographic pattern from that of a pure cystic to a mixed solid/cystic to an entirely solid lesion. Renal leiomyomas usually are sharply demarcated from the surroundings. Although computerized tomography cannot distinguish a renal leiomyoma from other benign or malignant renal processes the presence of invasion can virtually eliminate this benign tumor as a diagnosis. Since a preoperative diagnosis cannot be made, management involves renal exploration and radical nephrectomy in the larger lesions with a renal-sparing operation possible in selected cases. After treatment patients have a uniformly excellent prognosis.     

Childhood leiomyoma of kidney

Renal leiomyoma is a rare cause of hematuria and a rare renal tumor of childhood. It has minimal malignant potential and is difficult to distinguish clinically from Wilms tumor. All cases reported in the literature were treated by nephrectomy.     

Lymphangioma of the kidney

Lymphangiomas are rare benign tumors that are congenital malformations of the lymphatic system. Most cases present in children as a soft, cystic mass in the neck and the axilla. Primary renal lymphangioma is exceedingly rare, with only 35 cases reported so far. We report a case of primary lymphangioma arising from the kidney. A 59-year-old man was referred for evaluation of a right renal mass found in an abdominal ultrasonography during a health checkup. Abdominal ultrasonography and computed tomography (CT) revealed a 3.2 x 2.9 cm multiloculated cystic mass in the upper pole of the right kidney. We could not deny malignant disease such as cystic renal cell carcinoma with any diagnostic modalities. The patient was brought to surgery. During the surgical procedure, the tumor was suspected to be lymphangioma of the kidney as a result of a frozen- section histopathological evaluation. Therefore enucleation of the tumor was performed. Pathological evaluation of the specimen revealed lymphangioma arising from the kidney. The patient is free of disease after a 3-month follow-up period.     

Leiomyoma of the kidney. Differential diagnostic aspects of renal cell carcinoma with increasing clinical relevance

Renal leiomyoma is a rare benign tumor which has its origin in smooth muscle cells of different structures of the kidney. The clinical incidence of renal leiomyoma is much lower than the frequency described in large autopsy studies. Renal leiomyomas are mainly located in the renal capsula and pelvis or next to those structures. Clinical symptoms are nonspecific (e.g., flank pain or flank tumor) or completely absent, making most of the leiomyomas an incidental finding during routine diagnostics. A differential diagnosis between renal leiomyoma and renal cell carcinoma on the basis of medical imaging is extremely difficult. Therefore, laparotomy and nephrectomy are performed in most cases of suspected renal cell carcinoma. The definitive diagnosis of a leiomyoma is only possible after histological examination of the tumor. Due to the rising number of diagnoses resulting from improved medical imaging, renal leiomyomas are gaining more importance in the differential diagnosis of renal cell carcinoma, especially with respect to kidney-sparing surgery.     

Renal cancer

Renal cell carcinoma (RCC) is an adenocarcinoma of the renal cortex. It is the commonest type of kidney cancer and accounts for over 85% of renal cancer diagnoses. The remaining malignancies are transitional cell carcinomas, sarcomas, Wilms’ tumour, and rarely lymphomas and metastatic deposits. 10%–15% of renal masses are benign, such as oncocytomas and angiomyolipomas. Simple renal cysts are benign, however more complex renal cysts have a risk of being malignant. Renal cell carcinoma is commonly diagnosed at an earlier stage due to the widespread availability of imaging, and as a result the described classic triad of symptoms of haematuria, renal angle pain and a palpable mass is increasingly uncommon. The management of renal cancer includes active surveillance for older, comorbid patients, nephron-sparing surgery or ablative therapies for smaller renal masses, radical nephrectomy for larger tumours, and systemic treatment with a combination of immunotherapies and tyrosine kinase inhibitors and for metastatic disease.     

后腹腔镜与开放手术行肾部分切除术治疗肾肿瘤的临床效果比较

目的：通过与开放性肾部分切除术（OPN）的临床效果比较,评价后腹腔镜肾部分切除术（LPN）的临床价值。方法：回顾性分析后腹腔镜肾部分切除术（38例,LPN手术组）和同期施行开放性肾部分切除术（46例,OPN手术组）的临床资料,就两组患者一般资料、手术时间、患肾热缺血时间、术中出血量、术后肠道功能恢复时间、术后止痛药用量、术后住院天数、术后血清肌酐升高幅度及术后并发症等指标进行比较。根据数据类型选用x2检验、两样本t检验或Wilcoxon秩和检验,以P〈0．05为差异有统计学意义。结果：两组患者的一般资料差异无统计学意义（P〉0．05）,具有可比性。LPN手术组在术中出血量、术后肠道功能恢复时间、术后止痛药用量、术后住院天数方面及术后并发症发生率均优于DPN手术组（P〈0．05）,但前者的患肾热缺血时间明显长于后者（P〈0．05）。LPN手术组和OPN手术组的手术时间及术后血清肌酐升高幅度差异无统计学意义（P〉0．05）。两组患者送检标本的手术切缘均为阴性,随访18个月均无一例复发。结论：后腹腔镜肾部分切除术治疗肾肿瘤疗效肯定,与传统的开放性肾部分切除术相比,具有创伤小、恢复快、疗效与开放性手术相当等优点,是目前治疗肾肿瘤较理想的手术方法,值得进一步推广。     

Spontaneously ruptured multilocular cystic nephroma

Multilocular cystic nephroma is a relatively rare benign tumor of the kidney. An adult case of spontaneously ruptured multilocular cystic nephroma was reported. A 33-year-old woman who presented with a right flank colic attack. The preoperative diagnosis was spontaneously ruptured renal tumor. A right nephrectomy was performed. A multilocular cystic lesion, 10 cm in diameter, was found in the removed specimen, which had a hematoma inside and direct tumor extension into the renal pelvis. On microscopic examination, the surface of loculi was covered by a layer of hobnail epithelium, and septa were composed of fibrous tissue with dilated vessels, lacking in normal renal components. There were no signs of malignancy. The lesion extending into the renal pelvis showed the same microscopic findings. The final diagnosis was multilocular cystic nephroma. Two respects, spontaneous rupture and tumor extension into the renal pelvis, were unique to the present case. There has been no report of spontaneously ruptured mutilocular cystic nephroma. The tumor extension into the renal pelvis, however, has been found in several reports. This growth pattern might be one of the characteristics of this benign renal tumor.     

Laparoscopic partial nephrectomy for renal leiomyoma: a case report

A 60-year-old man visited our hospital with a complaint of right renal incidentaloma which was pointed out on abdominal ultrasonography for a medical check-up. Abdominal computed tomography showed a renal tumor in the right kidney, which was a slightly high-dense relative to the renal parenchyma and was enhanced in the arterial phase. The tumor had grown gradually from 1.4 to 1.7 cm in diameter. After the observation for 4 years, he underwent pure laparoscopic non-ischemic partial nephrectomy using a microwave tissue coagulator. Histological examination of the specimen revealed a leiomyoma of the kidney. This is the 5th case of successful laparoscopic partial nephrectomy for renal leiomyoma in Japan within the retrieved references.     

Renal artery pseudoaneurysm after laparoscopic partial nephrectomy for renal cell carcinoma in a solitary kidney

Abstract Renal artery pseudoaneurysms are a well‐documented complication following trauma or percutaneous urological procedures, but are rare after partial nephrectomy. We present the case of a 34‐year‐old woman who, after undergoing a left nephrectomy in childhood due to Wilms’ tumor, had a pseudoaneurysm in a solitary kidney after laparoscopic right partial nephrectomy with extraperitoneal approach for a renal cell carcinoma. The segmental renal artery feeding the pseudoaneurysm was embolized with coils without significant loss of residual renal function.     

囊性肾癌5例报告并文献复习

目的:探讨囊性肾癌的早期诊断及治疗方法。方法:回顾性分析2008年1月~2012年8月间收治的5例囊性肾癌患者的临床资料,1例术前影像学检查提示双侧肾脏占位病变,一侧为囊性占位病变;4例显示单侧肾脏单发囊性占位病变,左肾3例,右肾1例;其中男3例,女2例;年龄46~68岁,平均56.4岁;肿瘤体积21.84~208ml,平均101.96ml。按照Bosniak分类,Ⅱ类1例,Ⅲ类2例,Ⅳ类2例;T1期2例,T2期2例,T3期1例。3例术前诊断为囊性肾癌,1例为肾脏囊肿,1例为肾嗜酸性细胞瘤合并囊性肾癌。2例行肾癌根治术,2例行肾部分切除术,1例行囊肿去顶减压术后2周行肾癌根治术。并结合相关文献复习进行分析讨论。结果:5例患者术后病理检查报告证实为透明细胞癌2例,乳头状细胞癌1例,多房囊性肾癌1例,嗜酸细胞腺瘤伴囊性变1例。平均随访34.4个月(10~66个月),1例发生骨骼及肺部转移,余4例均无复发转移。结论:囊性肾癌是一种广义上的肾癌分类,有四种分型;与其他类型肾癌相比,大部分恶性程度较低。囊性肾癌的术前诊断主要依赖于影像学检查,对于可疑病例,术中需行快速冷冻病理检查。对此类肿瘤,建议行保留肾单位手术。     

Xanthogranulomatous pyelonephritis treated by partial nephrectomy

Xanthogranulomatous pyelonephritis is an uncommon disease in children. We report of a 2-month-old girl with urinary tract infection and with a renal mass detected by ultrasound scan. The preoperative differential diagnoses were Wilms tumor, multicystic dysplastic kidney, renal abscess, and mesoplastic nephroma. The subsequent histopathological findings allowed the diagnosis of xanthogranulomatous pyelonephritis (XGP). Although XGP is rare at this age, it must be considered in the differential diagnosis of a child presenting with renal mass, either with or without associated urolithiasis, anemia, and elevated inflammatory markers. The long-standing mainstay of therapy for diffuse XGP has been nephrectomy. However, we report the successful preservation of renal mass with partial nephrectomy for diffuse XGP. The affected kidney grew normally and preserved residual function after the operation. Hence we strongly suggest parenchymal saving in pediatric cases of XGP to preserve renal function.     

Metachronous bilateral Wilms tumor. Report of longest-known survivor and guidelines for conservative management

In a one-year-old black male patient a classic Wilms tumor of the left kidney was treated with left nephrectomy, chemotherapy, and irradiation to the entire abdomen. Two years later a mature Wilms tumor, consisting predominantly of rhabdomyomatous elements, was discovered in the right kidney. Although a second course of chemotherapy was given and 2,000 rad were delivered to the right flank, the mass continued to enlarge with progressive deterioration of renal function. A nephron-sparing procedure was performed, in which a 3,400-g tumor measuring 19 cm X 16 cm X 9 cm was enucleated from the right kidney without compromise to the remaining normal tissue. Pathologic examination of the surgical specimen revealed a mature Wilms tumor with a malignant anaplastic sarcoma arising in the central portion. Currently, he is disease-free with normal renal function more than twenty years after diagnosis of the metachronous bilateral Wilms tumor. We believe he is the longest known surviving metachronous Wilms tumor patient and emphasizes the importance of conservative, meticulous surgery in the management of both unilateral and bilateral Wilms tumors. The role of multimodal therapy (chemotherapy, irradiation, and surgery) as well as the current guidelines for the management of bilateral Wilms tumors as proposed by the National Wilms Tumor Study are reviewed.     

Two cases of leiomyoma of the kidney]

Renal leiomyomas large enough to be clinically diagnosed are extremely rare. We review 30 cases of clinically diagnosed renal leiomyoma from the literature in Japan, including our 2 new cases. Case 1: In a 52-year-old man with no symptoms a renal mass was found accidentally on an ultrasonogram. CT scan showed a mass with a cystic area at the upper pole of the right kidney. Angiogram showed a hypovascular mass. Case 2: CT scan revealed a cystic mass and angiogram showed an avascular mass at the upper pole of the left kidney in a 19-year-old man having gross hematuria and left flank pain. Transperitoneal nephrectomy was done in both cases. Histologically each tumor was composed of monotonous proliferation of spindle shaped cells without atypia, which showed intense immunoreactivity for alpha-smooth muscle actin. The diagnosis of benign leiomyoma was made in each case. In a review of 30 cases, we found that renal leiomyomas occur most often in female (77%), between decades 2 and 5 of life (median: 46 years). On the angiogram it appears most often as an avascular or hypovascular mass. CT scan shows cystic or mixed solid/cystic or solid lesion, occasionally with calcification. Preoperative diagnosis is extremely difficult to be made. Histologically, fibroma, angiomyolipoma, congenital mesoblastic nephroma and leiomyosarcoma should be differentiated.     

Open partial nephrectomy for tumor in a solitary kidney: experience with 400 cases

PURPOSE: We present a series of 400 patients with tumor in a solitary kidney who underwent open surgical partial nephrectomy performed by a single surgeon (ACN) with a primary focus on postoperative long-term kidney function. MATERIALS AND METHODS: A total of 400 patients with sporadic nonfamilial kidney tumors in a solitary kidney underwent open partial nephrectomy between 1980 and 2002. In 323 patients (81%) the contralateral kidney had been surgically removed, while the remaining 77 (19%) had a congenital solitary kidney. Renal insufficiency was present preoperatively in 184 patients (46%). Adverse risk factors for partial nephrectomy were present in a large percent of patients. Intraoperative and postoperative parameters were evaluated at a mean followup of 44 months. RESULTS: In the overall series 5 and 10-year cancer specific survival was 89% and 82%, respectively. Surgical complications occurred in 52 patients (13%), most commonly urinary leakage. Early postoperative renal function was achieved in 398 patients (99.5%). Only 2 patients required permanent dialysis postoperatively. Satisfactory long-term renal function was achieved in 382 patients (95.5%). A total of 18 patients had progressed to renal failure a mean of 3.6 years after surgery. Patient age, the amount of renal parenchyma resected, a congenitally absent or atrophic contralateral kidney and the time of contralateral nephrectomy were noted to be significantly associated with postoperative renal function. CONCLUSIONS: Open surgical partial nephrectomy can be safely performed in patients with tumor in a solitary kidney. Long-term cancer-free survival with the preservation of renal function can be reliably expected in most of these cases.     

Inflammatory pseudotumors of the kidney: a case report

Inflammatory pseudotumors are uncommon benign tumors of unknown etiology which may develop at several anatomical sites, e.g., the airways and gastrointestinal tissues, soft tissues, the orbit, the spleen, or the lymph nodes. The renal site is extremely rare, and presents the problem of differential diagnosis as the clinical and radiological aspects of this tumor are similar to those of an adenoma or an angiomyolipoma, and suggest the presence of a carcinoma, in particular a cystic renal carcinoma which is also a rare form of tumor. There is therefore a risk that this benign lesion could be misdiagnosed. Due to the good prognosis associated with this type of tumor, in cases where the definitive diagnosis has been established no surgical procedure is necessary. However, the difficulty in making this diagnosis preoperatively means that in general the organ has to be surgically removed so that a histological analysis can be made and the negative or positive findings confirmed. In the present study, the case of an inflammatory pseudotumor of the kidney has been described. In this instance, radical nephrectomy of the left kidney was carried out as the disease was presumed to be renal cell adenocarcinoma. However, the histopathological analysis was negative as regards malignancy, and indicated the presence of an inflammatory pseudotumor. This article raises the question of the problem in establishing a preoperative definitive diagnosis, as a correct diagnosis is often only confirmed following nephrectomy (in cases where the contralateral kidney is healthy).     

内生性、中央型微小肾癌的诊断和治疗（附3例报告及文献复习）

目的：探讨内生性、中央型微小肾癌的定义、诊断和治疗,提高其诊治效果。方法：回顾性分析3例内生性、中央型微小肾癌患者的临床资料,根据B超、CT、MRI检查确立内生性、中央型微小肾癌（〈2．0cm）诊断。采用保留肾单位的肾肿瘤切除术,术中在B超引导下行肾部分切除术,结合文献资料进行讨论。结果：3例患者肾肿瘤均〈2．0cm,不突出肾表面,术中肾脏外观正常,在B超引导下进行肾肿瘤切除,保留了肾功能。术后患者生化、B超、CT随访6个月～5年,肾功能良好．无肿瘤复发。结论：内生性、中央型微小肾癌诊断主要依靠CT和MRI,首选治疗方法为保留肾单位的肾肿瘤切除术,其预后较好。     

The accuracy of 250 fine needle biopsies of renal tumors

PURPOSE: In some cases of uncertain lesions in the kidney it would be helpful to perform biopsies for preoperative histopathological evaluation. In this study we evaluated the accuracy of and the impact on tumor management of core biopsy for histopathological evaluation of small solid renal masses. MATERIALS AND METHODS: After radical or partial nephrectomy 250 renal tumor biopsies were performed in 50 patients. All biopsies were performed by 1 urologist after preparation of the kidney ex situ on back table visually guided. Formalin fixed paraffin embedded biopsies were evaluated by 1 pathologist. RESULTS: In 49 of 50 cases (98%) we could define the malignant behavior of the tumor when performing 1 central and 4 peripheral biopsies of each tumor. In 85.2% the grading was correctly defined. A benign lesion was revealed in 4 cases (8%, all oncocytoma). In renal tumors 4 cm or smaller in diameter the accuracy of 1 central and 1 peripheral biopsy each regarding definition of tumor origin, tumor grading and cell type/growth pattern was 96% and 95.5%, 84% and 84.4%, and 87.5% and 89.5%, respectively. In renal tumors more than 4 cm in diameter the accuracy was 100% and 98.1%, 85% and 94.3%, and 71.4% and 88.7%, respectively. CONCLUSIONS: Core biopsy of renal lesions is accurate enough for histopathological evaluation and determination of therapeutic procedure. Additionally, biopsy could be used for identifying benign renal lesion for observation.     

Intravenous extended liposarcoma arising from renal sinus

Liposarcoma arising from the renal sinus is rare and there have been no reports of intravenous extended liposarcoma of the renal sinus thus far. We report a case of liposarcoma of the renal sinus that extended into the renal venous lumen. A 58-year-old woman was referred to our hospital for an intravascular fatty tumor of the right renal vein incidentally discovered by an abdominal screening ultrasonogram. Computer tomography revealed a fatty tumor extending from the right kidney to the right renal vein with no evidence of metastatic lesions. Total right nephrectomy and extirpation of the intravascular tumor of the right renal vein were carried out. Pathological findings showed well-differentiated liposarcoma of the renal sinus. The tumor invaded to the right renal vein and the renal parenchyma.     

Variants of renal angiomyolipoma closely simulating renal cell carcinoma: difficulties in the histological diagnosis

Renal angiomyolipoma is considered to be a benign renal tumor composed of atypical blood vessels, smooth muscles and fat cells. We report 2 cases of unilateral renal angiomyolipoma. In both cases, our preoperative diagnosis was renal cell carcinoma, because no low density area compatible with fat tissue was noted in the tumors on radiographic evaluation. Through histological examination, both tumors proved to be angiomyolipomas mainly composed of epithelioid cells in 1 case, and spindle-shaped smooth muscle cells mimicking a leiomyoma in the other case. Both patients are well showing no evidence of metastases 16 and 14 months after nephrectomy, respectively.     

Living donor renal transplantation with incidental renal cell carcinoma from donor allograft

To report our series of cases with living donor kidney transplant by laparoscopic nephrectomy with incidental renal cell carcinomas (RCC) at the time of transplant. We performed a search of cases of renal allografts from living donors with incidental tumors which were confirmed as RCC in final pathology. The graft nephrectomy was performed via hand‐assisted laparoscopic procedure. All cases underwent partial nephrectomy of the tumor during the back‐table preparation of the graft and sent for pathological analysis. We performed 435 living donor kidney transplants at our Institution and identified four cases consistent with the diagnosis of RCC. Two of them were clear cell type, one papillary and one multilocular RCC. All the tumors presented at stage I of TNM classification. After a median follow‐up of 36 months, three patients remain free of dialysis with good allograft function. One noncompliant patient presented with a glomerular filtration rate (GFr) below 15 ml/min after a BK viral infection. At the end of follow‐up period, all patients had remained free of tumor. Donors with suspicious renal masses might be accepted for living donation. Partial nephrectomy before transplantation could offer a cure for the disease without risks for the recipient with therapeutic benefit for the donor.