Metachronous renal tumours after surgical management of oncocytoma

Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? Oncocytoma is a benign renal tumour that cannot be differentiated from renal cell carcinoma radiographically. Follow‐up after surgery for oncocytoma is highly variable and the natural history of surgically treated renal oncocytoma is poorly defined. We sought to assess the risk of metachronous renal tumours in a cohort of patients treated surgically for renal oncocytoma. We report a large cohort of oncocytoma patients following surgical management. This study defines the risk of metachronous renal tumours after surgical treatment of renal oncocytoma. Our findings suggest that patients with metachronous renal tumours after treatment of renal oncocytoma may have a smaller risk of renal cell carcinoma compared with patients presenting with a primary renal mass. Our findings did not support concern for increased risk of renal cell carcinoma following surgical treatment of primary renal oncocytoma.

OBJECTIVE

? To assess the risk of metachronous renal cell carcinoma (RCC) and benign renal tumours after surgical treatment of primary renal oncocytoma.

PATIENTS AND METHODS

? Patients treated for primary renal oncocytoma between 1970 and 2007 were identified. Tumours were reviewed by a urological pathologist and patients were followed for subsequent renal tumours.

RESULTS

? Of 424 patients with a median follow up of 7.1 year, 17 (4.0%) patients were diagnosed with a metachronous renal tumour at a median of 3.0 years (range 0.3–16 years). Of the 17 metachronous tumours, eight were oncocytoma, four were RCC and five were not resected or biopsied. ? Eleven metachronous tumours occurred after solitary unilateral oncocytoma, five occurred after multifocal unilateral oncocytoma, and one occurred after multifocal bilateral oncocytoma. ? Estimated 10‐year tumour‐free and RCC tumour‐free survival was 94.8% and 98.7%, respectively. Patients with primary multifocal oncocytoma were at higher risk of metachronous tumour (hazard ratio 4.0; P = 0.007). Initial oncocytoma size (hazard ratio 1.1; P = 0.11) was not highly associated with risk of tumour recurrence.

CONCLUSIONS

? To our knowledge, we report the largest cohort of oncocytoma after surgical management. Metachronous renal neoplasm in a patient with previous oncocytoma is more likely to be benign compared with patients who present with a renal tumour for the first time. Multifocal primary oncocytoma is associated with metachronous renal tumours. ? Overall, the risk of metachronous RCC in a patient with an oncocytoma is similar to that of the general population, which does not support the use of routine cross‐sectioning imaging surveillance.     

Giant renal oncocytoma

We report the largest renal oncocytoma excised at the initial presentation and the second largest renal oncocytoma in published reports. Despite a tendency for renal oncocytomas to be relatively small and asymptomatic compared with renal cell carcinomas, these lesions cannot be reliably differentiated preoperatively. The variable nature of presentation and overlap of radiographic characteristics between these lesions complicates their clinical differentiation. The present case illustrates the difficulty in the preoperative diagnosis of even very large, enhancing renal masses and reinforces the inclusion of renal oncocytoma in the differential diagnosis of these lesions.     

Renal oncocytoma with bilateral synchronous renal cell carcinoma in a patient undergoing long-term hemodialysis

Abstract:   We report a case of bilateral synchronous renal cell carcinoma and renal oncocytoma in a 56-year-old male who had been treated with hemodialysis for 32 years. Because anemia gradually worsened, computed tomography and magnetic resonance imaging were carried out and revealed bilateral renal tumors within acquired cystic disease of the kidney. Bilateral nephrectomy was carried out, and the patient was diagnosed with multiple renal cell carcinomas and a single renal oncocytoma. To our knowledge, this is the first reported case of renal oncocytoma with synchronous renal cell carcinoma in a patient undergoing long-term hemodialysis.     

Renal oncocytoma in Taiwan

BACKGROUND: Renal oncocytoma has been repeatedly reported in Western countries, but only a few cases have been reported in Eastern countries. This study aims to review the clinical course of renal oncocytoma in an Eastern country such as Taiwan. MATERIALS AND METHODS: Sixteen cases of renal oncocytoma seen between 1987 and 2002 at Chang Gung Memorial Hospital, Taipei, Taiwan, were studied. RESULTS: Preoperatively, all patients were diagnosed to have renal cell carcinoma, following various radiologic studies. Perioperatively, frozen sections of three patients indicated renal oncocytoma in two and renal cell carcinoma in one. Renal oncocytoma has marked similarities to renal cell carcinoma, according to various radiologic, cytologic, and pathological investigations, so an accurate diagnosis is difficult to achieve, either preoperatively or perioperatively. Therefore, rather than being treated with partial nephrectomy, all patients were treated aggressively with unilateral radical nephrectomy. Postoperatively, all 16 patients were followed up, from 12 to 189 months, with a mean of 58.7 months. Notably, all patients survived with no evidence of tumor recurrence. CONCLUSIONS: The experience in Taiwan is generally that renal oncocytoma behaves benignly, as reported in other areas. The excellent prognosis associated with this tumor appears to indicate that partial nephrectomy may suffice for removing the tumor, while sparing other unaffected renal parenchyma.     

A case of renal oncocytoma with synchronous contralateral renal cell carcinoma

A case of bilateral, synchronous renal cell carcinoma and oncocytoma is reported. The patient was a 70-year-old woman. Computed tomographic scan revealed bilateral low density masses, which had a diameter of approximately 4 cm (right kidney), and 2.5 cm (left kidney). We suspected bilateral renal cell carcinomas, and performed, right nephrectomy and left enucleation of the tumor. Pathological diagnosis was right renal cell carcinoma and left oncocytoma. To our knowledge only 5 previous cases of renal cell carcinoma associated with oncocytoma have been reported in Japan. Two cases were metachronous and three cases were unilateral and synchronous. This is the first reported case of bilateral, synchronous renal cell carcinoma and oncocytoma.     

Paraneoplastic hypertension associated with renal oncocytoma: management with cryoablation

Paraneoplastic hypertension associated with a renal oncocytoma is an unreported syndrome. We report a unique case of a patient with multidrug-resistant hypertension who was found to have a solitary renal mass. Cryoablation was performed and resulted in an immediate and dramatic decrease in blood pressure. Histologic review of intraoperative biopsy specimens revealed findings consistent with renal oncocytoma. To our knowledge, this is the first report of hypertension in the setting of a renal oncocytoma, with subsequent improvement of this paraneoplastic syndrome after cryoablation.     

RENAL ONCOCYTOMA CONTAINING "CHROMOPHOBE" CELLS

We report a rare case of renal oncocytoma containing occasional "chromophobe" cells. This case suggests an intimate relationship between oncocytoma and "chromophobe" renal cell carcinoma.     

RENAL ONCOCYTOMA: MULTIFOCALITY, BILATERALISM, METACHRONOUS TUMOR DEVELOPMENT AND COEXISTENT RENAL CELL CARCINOMA

PURPOSE: We analyzed a large series of cases of renal oncocytoma to define the incidence of coexistent renal cell carcinoma, multifocality, bilateralism and metachronous tumor development. MATERIALS AND METHODS: Between 1980 and 1997, 100 men and 38 women with a mean age of 68 years with oncocytoma, were treated surgically at our institution. We analyzed tumor characteristics and reviewed specimens for coexistent renal cell carcinoma. RESULTS: Tumors were discovered incidentally in 58% of the cases. Specimens were obtained from 84 radical and 70 partial nephrectomies. Tumor size ranged from 0.3 to 14.5 cm. (median 3.2). Oncocytoma was unilateral in 131 cases (95%) and bilateral in 7 (5%), while there were multiple oncocytomas in 8 (6%). Mean followup was 41 months (range 0 to 200). The disease specific survival rate was 100% and no patient had metastasis. In 6 patients (4%) metachronous oncocytoma developed during followup. No patient had locally recurrent oncocytoma after partial nephrectomy for a solitary renal oncocytoma. Renal cell carcinoma and oncocytoma were found in 14 patients (10%), including unilateral synchronous disease in 9 and bilateral synchronous disease in 5. CONCLUSIONS: Our data support the benign nature of renal oncocytoma. Multifocality, bilateralism and metachronous tumor develop in approximately 4 to 6% of all cases. Renal cell carcinoma coexisted in 10% of oncocytoma cases.     

Oncocytoma associated with acquired cystic disease of kidney (ACDK): a case report

A case of renal oncocytoma associated with acquired cystic disease of kidney (ACDK) in a 56-year-old man is reported. He had received hemodialysis for 15 years because of chronic renal failure. Computed tomography (CT) was performed because of distention in the upper abdomen, revealing a right renal tumor. He underwent laparoscopic right nephrectomy, and was diagnosed with renal oncocytoma. There have been reported 8 cases of renal oncocytoma in hemodialysis patients, and our case was the third one associated with ACDK in the literature.     

Renal Oncocytoma in Taiwan

Background. Renal oncocytoma has been repeatedly reported in Western countries, but only a few cases have been reported in Eastern countries. This study aims to review the clinical course of renal oncocytoma in an Eastern country such as Taiwan. Materials and Methods. Sixteen cases of renal oncocytoma seen between 1987 and 2002 at Chang Gung Memorial Hospital, Taipei, Taiwan, were studied. Results. Preoperatively, all patients were diagnosed to have renal cell carcinoma, following various radiologic studies. Perioperatively, frozen sections of three patients indicated renal oncocytoma in two and renal cell carcinoma in one. Renal oncocytoma has marked similarities to renal cell carcinoma, according to various radiologic, cytologic, and pathological investigations, so an accurate diagnosis is difficult to achieve, either preoperatively or perioperatively. Therefore, rather than being treated with partial nephrectomy, all patients were treated aggressively with unilateral radical nephrectomy. Postoperatively, all 16 patients were followed up, from 12 to 189 months, with a mean of 58.7 months. Notably, all patients survived with no evidence of tumor recurrence. Conclusions. The experience in Taiwan is generally that renal oncocytoma behaves benignly, as reported in other areas. The excellent prognosis associated with this tumor appears to indicate that partial nephrectomy may suffice for removing the tumor, while sparing other unaffected renal parenchyma.     

肾嗜酸细胞腺瘤国内外平均发病年龄比较及文献分析（附24例报告）

目的：掌握我国肾嗜酸细胞腺瘤患者的平均发病年龄,提高其诊治水平。方法：回顾性分析24例肾嗜酸细胞腺瘤患者临床资料：发病年龄22-84岁,其中〈40岁2例,40～49岁10例,50-59岁3例,60-69岁5例,70～79岁2例,80-89岁2例。同时复习相关文献,比较国内外该病的平均发病年龄。结果：本组24例平均发病年龄为54．5岁,术后病理检查证实均为肾嗜酸细胞腺瘤。统计国内肾嗜酸细胞腺瘤224例平均发病年龄为52岁,国外397例平均发病年龄为66岁,国内发病年龄较欧美早14年。结论：肾嗜酸细胞腺瘤平均发病年龄国内与国外报道有明显差别,应引起临床重视。     

Renal oncocytoma: review of literature and report of six cases

6 cases of renal oncocytomas are described. Preoperative diagnosis is difficult in spite of new clinical diagnostic methods. In our series oncocytoma was diagnosed angiographically in 1 case and in 3 cases carcinoma was suspected. 5 of 6 cases, reevaluated postoperatively, fulfilled three of the four criteria of Ambos et al. for oncocytoma. Ultrasonography is a good exclusion diagnostic method for renal neoplasms. Oncocytoma may be suspected if the tumor projects nearly totally outside the renal contour as we found in 3 of our 6 cases. Aspiration biopsy smears have a diagnostic value in the evaluation of renal neoplasms. Cytologically we preoperatively diagnosed oncocytoma in 1 of 3 cases in which biopsy was performed. We warn, however, about the mosaic pattern of renal neoplasms. Renal cell carcinomas may have large areas composed of oncocytes. Frozen section analysis is a potentially hazardous peroperative diagnostic method in large tumors if oncocytoma is suspected.     

Case report of a symptomatic giant renal oncocytoma

Renal oncocytomas are benign tumours, often asymptomatic, and picked incidentally on radiological imaging. We present a case report of a symptomatic giant renal oncocytoma in a 61-year old man having lower back/right flank pain. A large right renal mass was identified on abdominal CT scan. Radiological features were not sufficient to differentiate this lesion from renal cancer. Right radical nephrectomy was performed. Typical features of oncocytoma, without evidence of malignancy, were seen on histological examination of the specimen. In this report, we discuss literature review of radiological, genetic, and pathological characteristics of renal oncocytoma.     

Magnetic resonance imaging of renal oncocytoma

Two cases of renal oncocytoma studied by magnetic resonance imaging (MRI) suggest that this new imaging modality may prove useful in the preoperative diagnosis of oncocytoma and its differentiation from renal cell carcinoma.     

肾嗜酸细胞瘤4例临床分析

目的:探讨肾嗜酸细胞瘤的临床、影像学及病理学特点,提高对肾嗜酸细胞瘤的诊疗水平。方法:回顾性分析4例肾嗜酸细胞瘤患者的临床资料:临床表现为右上腹痛2例,另2例体检发现。2例静脉尿路造影(IVU)检查提示占位性病变,超声、CT及肾动脉造影诊断为肾癌。4例均行肾癌根治性切除术,其中2例行腹腔镜手术,2例行开放性手术。结果:术后病理检查均诊断为肾嗜酸细胞瘤。术后B超随访6～15个月,4例均未出现复发和转移。结论:肾嗜酸细胞瘤是良性肿瘤,但临床症状、影像学表现与肾癌类似,需病理检查确诊。治疗上首选保留肾单位手术,术中冷冻切片活检可对手术提供重要信息。     

肾嗜酸细胞腺瘤伴潜在恶性1例报告并文献复习

目的：探讨肾嗜酸细胞腺瘤的诊断、治疗和预后,提高肾嗜酸细胞腺瘤的诊疗水平。方法：对本院1例肾嗜酸细胞腺瘤患者的临床特点、治疗方法、病理特征以及治疗预后进行分析,并结合文献探讨其鉴别诊断及治疗预后。结果：影像学诊断为肾脏肿物,术后病理学检查为肾嗜酸细胞腺瘤,灶性侵犯肾实质,伴潜在恶性。对其实施根治性肾切除术并术后免疫治疗。结论：肾嗜酸细胞腺瘤是一种罕见的肾脏良性肿瘤,极少数潜在恶性或恶变,男女均可发病,术前诊断较困难易误诊为肾癌。治疗首选保留肾单位手术,对有潜在恶性和恶性的以肾癌治疗指南来进行,并且密切随访。     

Update on oncocytoma

Oncocytoma is the most common benign solid renal tumor, comprising roughly 5% of resected renal masses. Typically discovered incidentally, oncocytoma is generally asymptomatic and very rarely metastasizes; however, multifocal disease and coexistence with renal cell carcinoma can occur. No currently used imaging techniques can reliably distinguish between oncocytoma and malignant lesions; therefore, patients must undergo resection, or in certain circumstances, biopsy, to definitively establish diagnosis. Careful attention to pathologic features and the adjunctive use of immunostains can aid in discriminating oncocytoma from other renal tumors characterized by granular, eosinophilic cytoplasm, especially chromophobe renal cell carcinoma. Nephron-sparing and laparoscopic surgical approaches can be used to treat appropriately selected patients.     

Bilateral multifocal renal oncocytoma

Renal oncocytoma is a rare benign tumor. Bilateral and multifocal renal oncocytoma has rarely been described in childhood. We report a 12-year-old girl who presented with massive left renomegaly and who was found to have bilateral cystic kidneys. A left nephrectomy was undertaken because of the renal enlargement, the radiological evidence of extensive disease, and to make a diagnosis. A diagnosis of multifocal oncocytoma was made after detailed histological examination.     

Renal oncocytomas--an Australian experience

A review was made of 24 cases of renal oncocytoma seen between 1978 and 1989. There was considerable overlap between the clinical presentation of renal oncocytomas and renal carcinomas. Although pre-operative radiological, cytological and pathological investigations may suggest the presence of an oncocytoma, these studies cannot make a definitive diagnosis. We recommend that these tumours be treated as potential renal carcinomas until post-operative microscopic evaluation proves otherwise.     

Renal oncocytoma—are there sufficient grounds to consider surveillance following prenephrectomy histologic diagnosis

IntroductionOncocytoma is a benign neoplasm of the kidney and comprises about 12% of all renal masses. A definitive preoperative diagnosis of oncocytoma is currently technically not feasible and its practical implication is controversial.ObjectivesTo analyze the current status of preoperative diagnostic tools for oncocytoma, study the different occurrences of oncocytoma-renal cell carcinoma (RCC) coexistence, including the phenomenon of true hybrid tumors, and investigate the rare reports on the natural history of unresected oncocytoma.Materials and methodsA PubMed search was performed using the following key word: oncocytoma, renal cell carcinoma, natural history, electron microscopy, and cytogenetics. Medline articles and abstracts prior to August 2009 were reviewed.Results and conclusionsAt the moment, preoperative renal mass biopsy is the only way for prenephrectomy histologic diagnosis of oncocytoma. However, it is expected that some of these biopsies, although suggestive for oncocytoma, will suspect chromophobe RCC. In all the English literature, the number of true ipsilateral synchronous hybrid oncocytoma-RCC tumors is extremely low in comparison with the “pure” oncocytomas being resected worldwide. There is almost no data on the natural history of oncocytoma.