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.     

乳头状肾细胞癌临床分析

目的：总结分析乳头状肾细胞癌的临床特点,提高其诊治水平.方法：回顾性分析2003～2009年收治的乳头状肾细胞癌的临床资料.并与同期53例肾透明细胞癌比较.结果：乳头状肾细胞癌组患者年龄57.3（47～78）岁,皆为男性,占同期肾细胞癌9.4%.就诊时3例无症状,2例出现肉眼血尿,1例双侧腰痛伴腹部包块.肿瘤平均最大径为6.6（2.6～16.0）cm,未见多中心病灶.TNM分期：T1a N0 M0 3例,T1b N0 M0 1例,T2 No M0 2例 病理分型I型3例,Ⅱ型3例 Fuhrman分级Ⅱ级2例,Ⅲ级4例.与肾透明细胞癌相比,乳头状肾细胞癌好发于男性,影像学检查不具备恶性肿瘤特征,确诊有赖于病理和免疫组织化学检查.临床分期皆为I期或Ⅱ期.就诊时无一例出现远处转移.结论：乳头状肾细胞癌在临床表现上与肾透明细胞癌相似,但在影像学表现、病理形态及生物学行为上均与肾透明细胞癌有所不同.根治性肾切除术是目前首选治疗方式.靶向治疗有可能成为转移性乳头状肾细胞癌治疗的新方向.     

乳头状肾癌的诊治（附32例报告及文献复习）

目的：提高乳头状。肾癌的诊治水平。方法：回顾性分析32例乳头状肾癌患者的临床资料。28例行开放性根治性肾切除术,3例行后腹腔镜下根治性肾切除术,1例行后腹腔镜下肾部分切除。结果：术后病理均为乳头状肾癌。采用2002年AJCC肾癌TNM病理分期：pT1oNoMo4例,pT1bNoMo14例,pT2oNoMo10例,pT2bNoMo1例,pTzbN·Mo1例,pT3oNoMo2例,病理分级：G121例,G210例,G31例。28例获16～30个月随访,平均20个月,2例死于心脏病,3例死于脑血管意外,1例局部复发,22例无瘤生存。结论：乳头状肾癌是一种具有特殊形态和表现的少见肾癌类型,部分。肾切除及根治性肾切除术是治疗乳头状。肾癌的首选方法,与其他类型肾细胞癌相比,乳头状肾癌预后较好。     

A case of renal mucinous tubular and spindle cell carcinoma

A 33-year-old man was hospitalized for treatment of a left renal tumor. The radiological findings were consistent with those of a left renal cell carcinoma (RCC). Subsequently, a radical nephrectomy was carried out. Macroscopic examination showed that a well-demarcated tumor measuring 2.9 × 2.6 × 2.5 cm was present in the middle portion of the resected kidney. The cut surface of the tumor was grayish-white in color. Pathological examination of the resected specimen showed a mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K). MTSCC-K is a low-grade renal epithelial neoplasm that has recently been recognized as a specific entity in the World Health Organization 2004 classification of RCC. To our knowledge, 17 cases of MTSCC-K in Japan have been reported by Japanese investigators. To avoid administration of excessive adjuvant treatment to patients, pathologists and urologists should consider this newly recognized low-grade malignancy when diagnosing renal tumors.     

Incidental renal tumours: the frequency of benign lesions and the role of preoperative core biopsy

OBJECTIVE: To determine the incidence of benign renal lesions in incidentally discovered small renal tumours, increasingly detected by the widespread use of abdominal imaging, and to evaluate whether preoperative renal core biopsy is effective in identifying benign lesions. MATERIALS AND METHODS: In a retrospective study, renal core biopsies for incidental tumours over a 5-year period were analysed. The biopsies were correlated with the final pathology of the nephrectomy specimens, or with patient follow-up if nephrectomy was avoided. RESULTS: Of 70 diagnostic core biopsies, a third of cases were considered benign. The sensitivity and specificity for both benign and malignant lesions when compared to definitive pathology was 100% in all cases subjected to nephrectomy. Of the 30 non-diagnostic biopsies, three were proved to be benign, and 18 likely to be benign. The only complication of renal biopsy was one case of bleeding after biopsy. CONCLUSION: A higher than previously anticipated proportion of incidentally detected small renal masses are benign. Given the high sensitivity and specificity, there is value in taking a core biopsy of small incidental renal lesions, a procedure with a low complication rate (1%). When analysed by a pathologist familiar with renal biopsy, this might avoid radical nephrectomy in many patients.     

Cystic neoplasms of the pancreas

As the use of cross-sectional imaging has become more frequent, there has been an increase in the diagnosis of cystic neoplasms and small non-functioning neuroendocrine neoplasms within the pancreas. Investigation and follow-up of cystic lesions of the pancreas requires a multimodal approach, of which endoscopic ultrasound with biopsy is becoming an increasingly important component. The main premalignant cystic neoplasms of the pancreas are mucinous-type tumours, intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). Main-duct IPMN should be resected due to the high incidence of underlying malignancy; however, a selective approach to intervention for side-branch IPMN should be taken (dependent on the presence of symptoms, tumour markers and tumour characteristics). Pancreatic neuroendocrine neoplasms (PanNENs) can also present as cystic lesions in approximately 18% of cases. Biochemically confirmed functional PanNEN and non-secreting PanNENs larger than 2 cm in size should be evaluated for surgery.     

Treatment options for renal cell carcinoma in renal allografts: a case series from a single institution

Renal cell carcinoma (RCC) is more common in renal transplant and dialysis patients than the general population. However, RCC in transplanted kidneys is rare, and treatment has previously consisted of nephrectomy with a return to dialysis. There has been recent interest in nephron‐sparing procedures as a treatment option for RCC in allograft kidneys in an effort to retain allograft function. Four patients with RCC in allograft kidneys were treated with nephrectomy, partial nephrectomy, or radiofrequency ablation. All of the patients are without evidence of recurrence of RCC after treatment. We found nephron‐sparing procedures to be reasonable initial options in managing incidental RCCs diagnosed in functioning allografts to maintain an improved quality of life and avoid immediate dialysis compared with radical nephrectomy of a functioning allograft. However, in non‐functioning renal allografts, radical nephrectomy may allow for a higher chance of cure without the loss of transplant function. Consequently, radical nephrectomy should be utilized whenever the allograft is non‐functioning and the patient's surgical risk is not prohibitive.     

Renal Fossa Recurrence of a Renal Cell Carcinoma 13 Years after Nephrectomy: A Case Report

Between 1980 and 1995, we performed a nephrectomy with curative intent on 183 patients with renal cell carcinoma at Nagoya University Hospital. Among these patients, 5 (2.7%) developed renal fossa recurrence (median follow-up, 65 months). We report a case of such a recurrence found 13 years after a nephrectomy for renal cell carcinoma (stage pT3a, pNO, MO). A 62-year-old female presented with a nodule on her back. Computed tomography and magnetic resonance imaging revealed a mass in the right back and retroperitoneum, and a biopsy revealed the tumor to be a renal cell carcinoma. Complete resection was performed, followed by administration of a-interferon. The patient is doing well 16 months after the operation. The case illustrates that very long-term follow-up after a nephrectomy is mandatory for patients with perinephric invasion of a renal cell carcinoma due to the risk of renal fossa recurrence.     

Living‐donor renal transplantation of grafts with incidental renal masses after ex‐vivo partial nephrectomy

OBJECTIVES

To assess transplantation of high‐risk kidneys with incidental renal masses (found occasionally during the routine evaluation of a living kidney donor) into recipients with limited life‐expectancy on haemodialysis, as this offers a potential solution to the current organ deficit.

PATIENTS AND METHODS

We detected five small (<2.3 cm), incidental, enhancing renal masses during donor evaluation. All patients had a standard metastatic evaluation. After laparoscopic donor nephrectomy a back‐table partial nephrectomy was performed and frozen‐section analysis was used to confirm both the diagnosis and negative surgical margins before transplantation.

RESULTS

Renal cell carcinoma was found in three of the five masses (one each cystic, clear cell and papillary; Fuhrman grades II, II and III, respectively) and the other two patients had angiomyolipoma. There were no long‐term complications in the transplanted kidneys. One patient developed delayed acute humoral rejection after transplantation and was treated appropriately. Both donor and recipient were followed with periodic imaging. At a median (range) last follow‐up of 15 (1–41) months, four patients were alive and one had died from complications after a fall. The cancer‐specific survival was 100%. There was no evidence of local recurrence in any patient at the last follow‐up.

CONCLUSION

Live donor kidneys with incidental small renal masses might be acceptable for transplantation in high‐risk recipients after careful back‐table partial nephrectomy.     

Quadruple renal neoplasia: bilateral renal tumors of dissimilar histogenesis.

Four separate renal neoplasms were removed from a 64-year-old man during a period of 8 months. A lesion was first identified in the left kidney and the nephrectomy specimen had 2 separate adenocarcinomas. A third adenocarcinoma and a papillary urothelial pelvic carcinoma were found subsequently and segmentally resected from the right kidney. The patient died 9 years later with local recurrence of the urothelial neoplasm but no evidence of metastatic carcinoma.     

乳头状肾细胞癌的临床特征分析（附7例报告）

目的：观察乳头状肾细胞癌的临床特点,提高对其诊断要点、治疗及预后的认识。方法：回顾性分析7例乳头状肾细胞癌患者的临床资料,复习相关文献,并对患者进行随访。结果：7例患者均经病理证实为乳头状肾细胞癌,1例并发肾上腺腺瘤;首发症状主要以腰痛、血尿、消瘦、低热为主;CT影像均提示肿瘤密度在肾髓质期强化程度明显弱于肾皮质,且在肾髓质期和排泄期呈均匀强化;6例经腹行根治性肾切除,1例经腰行根治性肾切除,术后均辅以免疫治疗,未行放化疗;6例获随访,随访时间为3个月～2年,1例于术后6个月出现急性肾衰死亡,1例于12个月因肝及淋巴结转移死亡,其余4例在随访期间未出现复发和转移,无瘤生存至今。结论：乳头状肾细胞癌与其它肾细胞癌在临床表现上基本相同,但在影像学表现,病理形态及生物学行为上均与其他类型的肾细胞癌不同,诊断主要依靠CT影像,确诊有赖于病理和免疫组织化学检查,早期手术是首选治疗方式,其预后可能与分期及转移有关。     

肾癌根治术后局部复发的再手术治疗12例报告

目的:探索手术治疗肾癌根治术后单纯局部复发的可行性。方法:回顾性分析2005年6月~2010年5月间12例肾癌根治术后局部复发再手术治疗患者的临床资料,并将其结果与近20年的文献报道结果进行比较。结果:9例患者完整切除复发肿块(包括1例肿块切除及下腔静脉血管置换术),3例只能活检后行微波消融治疗。手术时间60~188min,平均120min;完整切除者失血200~2 000ml,中位失血量1 200ml;无围手术期死亡病例。在平均随访27.2个月内,5例因转移性疾病死亡,其生存期2.6~17个月,平均生存期为7.8个月。存活患者中,2例再次复发,生存期4~48个月,平均生存期为15.6个月。结论:肾癌根治术后单纯局部复发再手术治疗可提高患者生存期,但手术存在失血多、风险大之可能。     

嗜酸性乳头状肾细胞癌1例报告并文献复习

目的：探讨嗜酸性乳头状肾细胞癌（oncocyticpapillaryrenalcellcarcinoma,OPRCC）的l临床特征。方法：回顾性分析本院收治的1例OPRCC,并结合文献资料分析OPRCC的诊断、治疗及预后。患者因左侧腰痛就诊,CT检查发现左肾占位性病变,考虑肾癌可能性大,予肾部分切除术。结果：术后病检报告为嗜酸性乳头状肾细胞癌,患者术后未接受辅助化疗,随访6个月无肿瘤复发及转移。结论：OPRCC十分罕见,但进展较慢,恶性程度低,早期扩散转移少见,预后较好,其确诊主依靠病理组织学检查。     

De Novo Kidney Graft Tumors: Results From a Multicentric Retrospective National Study

De novo tumors in renal allografts are rare and their prevalence is underestimated. We therefore analyzed renal cell carcinomas arising in renal allografts through a retrospective French renal transplant cohort. We performed a retrospective, multicentric survey by sending questionnaires to all French kidney transplantation centers. All graft tumors diagnosed after transplantation were considered as de novo tumors. Thirty‐two centers participated in this study. Seventy‐nine tumors were identified among 41 806 recipients (Incidence 0.19%). Patients were 54 men and 25 women with a mean age of 47 years old at the time of diagnosis. Mean tumor size was 27.8 mm. Seventy‐four (93.6%), 53 (67%) and 44 tumors (55.6%) were organ confined (T1–2), low grade (G1–2) and papillary carcinomas, respectively. Four patients died of renal cell carcinomas (5%). The mean time lapse between transplantation and RCC diagnosis was 131.7 months. Thirty‐five patients underwent conservative surgery by partial nephrectomy (n = 35, 44.3%) or radiofrequency (n = 5; 6.3%). The estimated 5 years cancer specific survival rate was 94%. Most of these tumors were small and incidental. Most tumors were papillary carcinoma, low stage and low grade carcinomas. Conservative treatment has been preferred each time it was feasible in order to avoid a return to dialysis.     

LACK OF RETROPERITONEAL LYMPHADENOPATHY PREDICTS SURVIVAL OF PATIENTS WITH METASTATIC RENAL CELL CARCINOMA

PURPOSE: Patients with metastatic renal cell carcinoma have a reported 5-year survival of 0% to 20%. The ability to predict which patients would benefit from nephrectomy and interleukin-2 (IL-2) therapy before any treatment is initiated would be useful for maximizing the advantage of therapy and improving the quality of life. MATERIALS AND METHODS: A retrospective analysis of the x-rays and charts of patients treated at the National Institutes of Health Surgery Branch between 1985 and 1996, who presented with metastatic renal cancer beyond the locoregional area and the primary tumor in place, was performed. Preoperative computerized tomography or magnetic resonance imaging, or radiological reports if no scans were available, were used to obtain an estimate of the volume of retroperitoneal lymphadenopathy. Operative notes were used to evaluate whether all lymphadenopathy was resected or disease left in situ, or if any extrarenal resection, including venacavotomy, was performed. Mean survival rate was calculated from the time of nephrectomy to the time of death or last clinical followup. If patients received IL-2 therapy, the response to treatment was recorded. Mean survival and response rate for IL-2 were compared among patients in 3 separate analyses. Patients without preoperatively detected lymphadenopathy were compared with those with at least 1 cm.3 retroperitoneal lymphadenopathy. Also, the patients who had detectable lymphadenopathy were divided into subgroups consisting of all resected, incompletely resected, unresectable and unknown if all disease was resected. Each subgroup was compared with patients without detectable preoperative lymphadenopathy. Patients with less than were compared to those with greater than 50 cm.3 retroperitoneal lymphadenopathy. Patients undergoing extrarenal resection at nephrectomy (complex surgery) due to direct invasion of the tumor into another intra-abdominal organ were compared with those undergoing radical nephrectomy alone, regardless of lymph node status. Statistical analysis was done with the Mantel-Cox test for comparison of survival on Kaplan-Meier curves and with Fisher's exact test for response rates for IL-2. RESULTS: A total of 154 patients with metastatic renal cell carcinoma underwent cytoreductive nephrectomy as preparation for IL-2 based regimens. There were 82 patients with metastatic renal cell carcinoma and no preoperative retroperitoneal lymphadenopathy who survived longer (median 14.7 months) than the 72 with lymphadenopathy (median 8.5, p = 0.0004). Patients with incompletely resected, unresectable or an unknown volume resected had decreased survival compared to those with no retroperitoneal lymphadenopathy. A multivariate analysis of survival was performed evaluating the known prognostic indicators, performance status and tumor burden, as represented by the number of organs involved with metastases, and the new prognostic factor, lymphadenopathy. Lymphadenopathy was more closely associated with survival than performance status, and appeared to be a new prognostic variable. Patients with and without retroperitoneal lymphadenopathy at initial presentation had similar rates for treatment with IL-2 (54% for both groups). Of the 82 patients with no lymphadenopathy 11 (13%) had long-term survival greater than 5 years. Of the 6 complete responses to IL-2, 5 occurred in this group. Only 1 other patient with incompletely resected retroperitoneal lymphadenopathy survived longer than 5 years. No significant difference in survival was seen between patients who did or did not undergo complex surgery. CONCLUSIONS: Patients who presented with metastatic renal cancer and retroperitoneal lymphadenopathy had a shorter survival than those with no detectable retroperitoneal lymphadenopathy. It is warranted to continue to perform complex extrarenal resection during nephrectomy since no significant difference in the response rate for IL-2 or mean survival compared with those of patients undergoing nephrectomy alone is currently detectable.     

A case of oncocytic papillary renal cell carcinoma

Papillary renal cell carcinomas (RCC) are the second most frequently identified pathological subtypes of RCC. Occasionally, papillary RCC demonstrate pathological characteristics of renal oncocytomas (RO), benign renal tumors. We report the case of an 81-year-old woman with an oncocytic papillary RCC, which was difficult to differentiate from a hybrid of RO and papillary RCC, who underwent left radical nephrectomy. Morphological examination showed oncocytic tumor region and partially scattered regions with papillary structure. Immunohistochemical examinations demonstrated strongly positive staining of α-methylacyl-CoA racemase in the papillary region and negative staining of progesterone receptor and CD117 in both regions. Fluorescence in situ hybridization confirmed the increased number of copies of chromosome 7 in the papillary region. Comprehensively, this case could be diagnosed as oncocytic papillary RCC. No evidence of disease recurrence was found at 12 months' follow up.     

Incidental angiomyolipoma resected during renal surgery for an enhancing renal mass

OBJECTIVE

To review the outcomes of surgery for renal angiomyolipoma (AML, a benign renal neoplasm that often appears as an enhancing renal mass on imaging) removed at a centre that manages AML conservatively, as typically the presence of tumour fat content detected on imaging leads to its diagnosis, but occasionally these tumours resemble conventional RCC, leading to their surgical extirpation.

PATIENTS AND METHODS

We retrospectively report data on 44 consecutive patients who had renal surgery with a pathological diagnosis of AML at our institution from 1988 to 2008. Patient demographics, intraoperative variables and postoperative outcomes are reported.

RESULTS

Of the 44 patients (40 women, 91%, and four men, 9%), most were asymptomatic (36, 82%), were unsuspected on imaging (40, 91%), had a solitary lesion (38, 86%), and all had a normal contralateral kidney. Patients had either a partial nephrectomy (38, 86%) or radical nephrectomy (six, 14%). The median (range) tumour size was 2.5 (0.6–19) cm. Perioperative complications occurred in 10 patients (23%), and a total of seven renal units (16%) were lost. Ten patients (23%) had chronic kidney disease (CKD) before surgery, while new onset CKD developed in six (14%) at the last follow‐up. There were no recurrences and there was one unrelated death at a median follow‐up of 28 months.

CONCLUSIONS

AML is a benign renal neoplasm that should be treated conservatively. Surgical intervention should be avoided, when possible, as it can lead to perioperative complications, loss of renal units, and development of CKD.     

Neoplasia papilar de polaridad inversa: un nuevo subtipo de tumor renal de buen pronóstico

IntroductionPapillary renal cell neoplasm with reverse polarity (PRNRP) has recently been recognized as an entity separate from the traditional classification of papillary renal cell carcinomas, due to its specific histopathological, immunophenotypic and molecular characteristics, as well as its indolent behavior.Material and methodsWe provide 6 new cases and a review of the literature published until the present time, which comprises a total number of 104 cases.ResultsOur PRNRP cases correspond to 5 men and one woman aged between 47 and 91 years. In 5 of the 6 cases, the PRNRP was an incidental finding in nephrectomy specimens. Nephrectomy had been indicated due to the presence of another renal tumor, except for one case, in which surgical intervention was indicated due to PRNRP. Our cases present mass sizes between 2 and 13 mm, as well as papillary histology with a monolayered lining of eosinophilic cells with low-grade nuclei in apical location. Immunohistochemically, they show a constant positivity for GATA3 and negativity for vimentin. KRAS mutations were identified in 50% of our cases. After a follow-up ranging between one and 60 months, 5 of the cases were still alive without recurrences or metastases, and one died from urothelial carcinoma.ConclusionsOur cases agree with the clinical and pathological characteristics described in the PRNRP cases published to date. With the present study, we provide the first series of national cases corroborating the existence of well-defined and constant diagnostic criteria that allow PRNRP to be considered as a distinctive entity.     

Cyst-associated renal cell carcinoma: Clinicopathologic characteristics and evaluation of prognosis in 27 cases

BACKGROUND: No consistent clinicopathologic characteristics of cyst-associated renal cell carcinoma (CRCC) have previously been determined. METHODS: In total, 768 patients with renal cell carcinoma (RCC) underwent radical or partial nephrectomy. Renal cell carcinoma was classified as CRCC in 27 of these patients (3.5%, subdivided into RCC originating in a cyst and cystic RCC), clear-cell RCC in 662 patients (86.2%), chromophobe cell renal carcinoma in 36 patients (4.7%) and papillary RCC in 43 patients (5.6%) according to the criteria of the World Health Organization. RESULTS: The pathologic stage and nuclear grade were usually lower in those with CRCC (low stage/low grade; 89%/96%) or chromophobe cell renal carcinoma (low stage/low grade; 89%/80%) than in those with clear-cell RCC (low stage/low grade; 59%/65%) or papillary RCC (low stage/low grade; 53%/69%). Of the 27 CRCC patients, only 19 (70%) could be diagnosed through preoperative imaging studies. Patients with CRCC showed a favorable prognosis (survival rate: 95% at 1 year, 89.7% at 3 years and 84.4% thereafter) and, especially among the patients with RCC originating in a cyst, no cancer-related death was observed. Comparing the survival among four types of RCC, a favorable outcome was observed in cases of CRCC or chromophobe cell renal carcinoma compared with clear-cell RCC or papillary RCC (clear vs chromophobe: P = 0.002; chromophobe vs papillary: P = 0.019; clear vs cyst-associated: P = 0.001; papillary vs cyst-associated: P = 0.00079). CONCLUSIONS: In cases of CRCC, the disease was usually detected at lower stages and grades and therefore the prognosis was better than in cases of other types of RCC. Preoperative diagnosis of this disease was very difficult, especially in cases of RCC originating in a cyst.     

Variants and Variations in Epithelial Renal Cell Tumors in Adults: The Pathologist's Point of View

Context and ObjectivesThe Vancouver consensus conference of the International Society of Urological Pathology provided the foundation for the 2016 World Health Organization (WHO) classification of the renal tumors.The aim of this contribution is to review some of the major changes and additions to tumor variants and variations in the current classification of the renal cell neoplasms in adults.Evidence acquisition and Evidence synthesisSeveral publications report no recurrence or metastasis in patients with multilocular cystic renal cell carcinoma (RCC). Multilocular cystic renal neoplasm of low malignant potential is now the term recommended by the WHO for this lesion.A similar recommendation has been made in the current literature for hybrid oncocytic/chromophobe tumors (ie, oncocytic neoplasia of uncertain malignant potential) and for clear cell papillary renal cell carcinoma (ie, neoplasm of low malignant potential). Some of the latter tumors were referred to as renal angioadenomatous tumors.Papillary RCC has traditionally been subdivided into type 1 and type 2 papillary RCCs. Recent molecular studies suggest that type 2 papillary RCCs may not constitute a single well-defined entity. There are newly recognized epithelial renal tumor entities in the 2016 WHO classification such as succinate dehydrogenase-deficient RCC.Conclusions and Patient summaryThere are some additional variations in the tumor types that are not included in the WHO classification, however, worth knowing, such as clear cell RCC with hemangioblastoma-like features and unclassified RCC with medullary phenotype.