Clear cell papillary renal cell carcinoma with angiomyomatous stroma: a histological,immunohistochemical, and fluorescence in situ hybridization study

Clear cell papillary renal cell carcinoma (CCPRCC) is a novel tumor entity that was recently recognized as a new distinct epithelial tumor within the current classification system. Nonclassic morphologic variants have rarely been reported. We present six challenging cases of CCPRCC with prominent (>75 %) tubular, acinar, and/or solid component and angioleiomyomatous stroma. The tumors lacked well-organized papillary architecture. All tumors had a variously thick capsule formed by a layer of bands of smooth muscle. The leiomyomatous tissue often entirely encased patches of tubular structures, or it formed only small leiomyomatous islands within the epithelial component. There was a remarkable relationship between the vascular network and the epithelial component in the sense that every single tubule or acinus was associated with a fine capillary network, with the capillaries intimately surrounding the tubular or acinar circumference. CCPRCC with variant morphology expressed carbonic anhydrase IX (CA-IX) in cup-shaped distribution. In addition, the tumor cells stained positive for cytokeratin 34betaE12, CK7, and vimentin. Renal cell carcinoma (RCC), P504s/AMACR, Melan A, and HMB45 were negative in tumor cells in all cases examined. Fluorescence in situ hybridization studies showed the presence of a normal copy number for chromosomes 7, 17, 3q, and 3p. CCPRCC with variant morphology seems to have a favorable prognosis. In the current series, tumor stage was low at presentation, and none of the patients had local recurrence or metastatic disease. The distinction between CCPRCC with variant morphology and clear cell RCC is critical because no case of CCPRCC has behaved aggressively.     

Clear cell papillary renal cell carcinoma: a clinicopathologic analysis of 6 cases

Clear cell papillary renal cell carcinoma (CCPRCC) is a newly described variant of renal cell carcinoma (RCC) which is composed mainly of cells with clear cytoplasm arranged in cystic and papillary patterns. We report the clinicopathologic features, prognosis and differential diagnosis of 6 Clear Cell Papillary Renal Cell Carcinomas. The clinical information and follow-up data were analyzed. The patients were six males with median age of 52.5 years. Case 1 revealed dense calcification and ossification. Cases 2 and 3 contain a variably prominent smooth muscle stromal component. CA-IX, CK7, PAX-8 and VIM were positive in all cases. TFE3 and AMACR were not expressed in any tumor. CD10 was negative in 5 of 6 cases .The patients were followed for 13~55 months with no local tumor recurrences and tumor metastasis. The CCPRCC was associated with a more favorable outcome. These were low-grade and low-stage renal tumors. No lymph node or distant metastasis of the six tumors.     

Clear cell papillary renal cell carcinoma: a clinicopathological study emphasizing ultrastructural features and cytogenetic heterogeneity

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently recognized renal neoplasm, which was initially described in end-stage renal disease (ESRD), but some cases have been reported in otherwise normal kidneys. We report a series of 11 CCPRCC (age range, 33-72 years; male-to-female ratio, 8:3). Follow-up was available for 8 patients. No patients developed local recurrence, distant or lymph-node metastasis, or cancer death. Histologically, all tumors exhibit morphologic features typical of CCPRCC including a mixture of cystic and papillary components, covered by small to medium-sized cuboidal cells with abundant clear cytoplasm. All 11 cases exhibited moderate to strong positivity for CK7, CA9, Vim, and HIF-1α, coupled with negative reactions for CD10, P504S, and RCC. We did not find any VHL gene mutations in all 11 cases. Losses of chromosomes 3 (monoploid chromosome 3) was detected in 3 cases. Ultrastructurally, the tumor cells composed of numerous glycogens with scanty cell organelles, reminiscent of clear cell renal cell carcinoma (CCRCC). In conclusion, the coexpression of CA9 and HIF-1α in the absence of VHL gene abnormalities in CCPRCC suggests activation of the HIF pathway by mechanisms independent of VHL gene mutation. Losses of chromosomes 3 (monosomies chromosome 3) was detected in 3 cases suggesting that at least some of these lesions have demonstrated abnormalities of chromosomes 3. Ultrastructurally, CCPRCC composed of numerous glycogens with scanty cell organelles, reminiscent of CCRCC suggesting the close pathogenesis relationship of CCPRCC with CCRCC.     

Useful immunohistochemical panel for differentiating clear cell papillary renal cell carcinoma from its mimics

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently described low-grade renal cell tumor. In this study, we investigated the expression of paired box 8 (PAX-8), carbonic anhydrase IX (CA IX), CK7, and α-methylacyl-CoA-racemase (AMACR) in this tumor by immunohistochemistry in a group of 20 cases of CCPRCC. Clear cell papillary renal cell carcinoma showed diffuse (70%) or intermediate (30%) nuclear positivity for PAX-8 in each case, with predominantly moderate intensity (50%). Ninety percent of the cases showed some degree of cytoplasmic staining for CA IX, predominantly with moderate intensity (50%). In addition, each case of CCPRCC also showed diffuse membranous staining for CK7. Most CCPRCCs (95%) were negative for AMACR. PAX-8, CA IX, CK7, and AMACR comprise a concise panel for distinguishing CCPRCC from its mimics. PAX-8 positivity helps to confirm the renal origin of this tumor. Positivity for CA IX and CK7 differentiate CCPRCC from conventional clear cell renal cell carcinoma, which is usually CA IX positive while CK7 negative. The CK7-positive and AMACR-negative pattern seen in CCPRCC differentiates it from papillary renal cell carcinoma, which is usually positive for both AMACR and CK7.     

Clear cell papillary renal cell carcinoma and clear cell renal cell carcinoma arising in acquired cystic disease of the kidney: an immunohistochemical and genetic study

Clear cell papillary renal cell carcinoma (RCC) is a recently established disease entity. However, there are few reports on genetic study of this entity. We report such a case with focus on genetic study. A 57-year-old Japanese man was found to have 3 renal tumors. Histologically, two tumors showed findings of clear cell RCC; and the other tumor showed findings of clear cell papillary RCC that was characterized by papillary growth pattern of neoplastic cells in cystic space with purely clear cell cytology. Immunohistochemically, tumor cells of clear cell papillary RCC were diffusely positive for PAX2 and cytokeratin 7, but negative for CD10, RCC Ma, and AMACR. In fluorescence in situ hybridization study for one clear cell papillary RCC, we detected polysomy for chromosome 7 and monosomy for chromosomes 17, 16, and 20. In addition, we detected mutation of VHL gene in clear cell RCC, but found no VHL gene mutation in clear cell papillary RCC. Finally, our results provide further evidence that clear cell papillary RCC may be both morphologically and genetically distinct entity from clear cell RCC and papillary RCC.     

Targeted next‐generation sequencing and non‐coding RNA expression analysis of clear cell papillary renal cell carcinoma suggests distinct pathological mechanisms from other renal tumour subtypes

Clear cell tubulopapillary renal cell carcinoma (CCPRCC) is a recently described rare renal malignancy that displays characteristic gross, microscopic and immunohistochemical differences from other renal tumour types. However, CCPRCC remains a very poorly understood entity. We therefore sought to elucidate some of the molecular mechanisms involved in this neoplasm by carrying out targeted next‐generation sequencing (NGS) to identify associated mutations, and in addition examined the expression of non‐coding (nc) RNAs. We identified multiple somatic mutations in CCPRCC cases, including a recurrent [3/14 cases (21%)] non‐synonymous T992I mutation in the MET proto‐oncogene, a gene associated with epithelial‐to‐mesenchymal transition (EMT). Using a microarray approach, we found that the expression of mature (n = 1105) and pre‐miRNAs (n = 1105), as well as snoRNA and scaRNAs (n = 2214), in CCPRCC cases differed from that of clear cell renal cell carcinoma (CCRCC) or papillary renal cell carcinoma (PRCC) tumours. Surprisingly, and unlike other renal tumour subtypes, we found that all five members of the miR‐200 family were over‐expressed in CCPRCC cases. As these miRNAs are intimately involved with EMT, we stained CCPRCC cases for E‐cadherin, vimentin and β‐catenin and found that the tumour cells of all cases were positive for all three markers, a combination rarely reported in other renal tumours that could have diagnostic implications. Taken together with the mutational analysis, these data suggest that EMT in CCPRCC tumour cells is incomplete or blocked, consistent with the indolent clinical course typical of this malignancy. In summary, as well as describing a novel pathological mechanism in renal carcinomas, this study adds to the mounting evidence that CCPRCC should be formally considered a distinct entity. Microarray data have been deposited in the GEO database [GEO accession number (GSE51554)]. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Clear cell papillary renal cell carcinoma with characteristic morphology and immunohistochemical staining pattern

Clear cell papillary renal cell carcinoma is newly-defined entity initially believed to be associated with end stage renal disease. We report a rare case of this neoplasm in a 70-year-old female patient with no known history of end-stage renal disease who presented with haematuria lasting several days. After initial workup, a computed tomography (CT) scan was performed and revealed a cystic mass in the right kidney. Material obtained by fine needle aspiration (FNA) biopsy of the mass was felt to be suspicious for renal cell carcinoma. The patient subsequently underwent right nephrectomy, and the lesional tissue was examined microscopically. A 2.3 cm in greatest dimension cystic space circumscribed by a fibrous wall was surfaced by a single layer of bland cuboidal cells with abundant clear cytoplasm. The solid component of the tumour consisted of branching papillae with delicate fibrovascular cores and uniformly lined by cells similar to those of the inner wall of the cyst. Some of the fibrovascular cores were markedly expanded by a myxoid-appearing substance, but no foamy cells were appreciated. Immunohistochemically, the neoplastic cells were diffusely immunoreactive with cytokeratin 7 (CK7), epithelial membrane antigen (EMA), high molecular weight cytokeratin (HMWCK) and vimentin. Neoplastic cells were only focally immunoreactive with CD10, and were negative for both p63 and alpha-methylacyl-CoA racemase (AMACR) (P504S). The cytomorphological features and immunohistochemical staining pattern of this tumour was consistent with that of clear cell papillary renal cell carcinoma (CCPRCC), as described by Gobbo et al.     

Renal clear cell tumors: morphology, histochemistry, ultrastructure, differential diagnosis

To define criteria for differential diagnosis of renal clear cell adenoma and grade I clear cell carcinoma, morphological, morphometric, histochemical, and ultrastructural studies were undertaken to examine 30 renal clear cell tumors (18 carcinomas and 12 adenomas). No morphological, morphometric, histochemical, and ultrastructural differences were found between the tumors, but the average tumor size was smaller in the adenoma than in the carcinoma. Clinically and morphologically, clear cell adenoma should be classified as grade I clear cell carcinoma of stage I, which has a relatively favourable prognosis by virtue of its small node sizes.     

Surgical pathology of cystic renal cell carcinomas: is there an overestimation of malignancy?

Most cystic renal epithelial tumors have excellent prognosis after resection despite the high proportion of renal cell “carcinoma” diagnosis. The 2019 Bosniak classification revision and recent downgrading of multilocular cystic renal cell carcinoma (RCC) to multilocular cystic renal neoplasm of low malignant potential (MCNLMP) may help reduce the discrepancy. Cystic clear cell (CC) RCC has been shown to behave favorably compared to non-cystic CC RCC and suggests a continuum with MCNLMP which would represent the most indolent of this spectrum. Further, the current pathological criteria distinguishing MCNLMP and extensively (>75%) cystic CC RCC should be revisited as both tumors show similar excellent prognosis. Clear cell papillary (CCP) RCC, which often has cystic change, should be renamed as “clear cell papillary neoplasm of low malignant potential”. However, cystic (and pseudocystic) features may also occur in other non-CC RCC types, including uncommon aggressive tumors with metastatic potential. This review highlights the need for reappraisal of the pathological categorization of cystic RCCs including the cystic CC RCC and CCP RCC.     

Renal cell carcinoma with intratumoral calcium oxalate crystal deposition in patients with acquired cystic disease of the kidney

We describe 2 cases of renal cell carcinoma arising in acquired cystic disease of the kidney (ACDK) in patients with end-stage renal disease undergoing hemodialysis for more than 5 years and provide a brief review of the complications of ACDK. In both cases, abundant calcium oxalate crystals were observed within the tumors. Histologically, one of the tumors was a conventional (clear cell) renal cell carcinoma. The other tumor was a bilateral papillary renal cell carcinoma. Both tumors were high-grade carcinomas with extensive oncocytic (acidophilic) features. Also noted within the kidneys were cysts with atypical papillary hyperplasia. The clinicopathologic findings along with review of the literature suggest a relationship between tumor growth and calcium oxalate crystal deposition in patients undergoing hemodialysis with ACDK.     

Tubulocystic carcinoma of the kidney: a histologic, immunohistochemical, and ultrastructural study

Tubulocystic carcinoma of the kidney (TCCK) is a tumor entity, which is not yet included in the WHO classification of renal tumors. The histogenesis of this neoplasm is uncertain. This study was undertaken to determine (1) the incidence of TCCK and (2) immunohistochemical and ultrastructural characteristics of those tumors that qualify as TCCK by the current definitions. From January 1, 2003 to December 31, 2012, a total of 615 renal cell carcinomas (RCCs) were seen by the Department of Pathology, University of Maryland Medical Center. Four TCCKs were identified (4/615, <1 %). TCCK is a distinctive group of kidney tumors with a male predominance and noteworthy macroscopic spongy appearance. Microscopically, the tumors were composed of tubules and cysts lined by a single layer of eosinophilic, columnar, cuboidal, flat, or hobnail cells with large nuclei and prominent nucleoli separated by a thin fibrotic stroma. In all TCCKs, the majority of neoplastic cells showed immunohistochemical (CD10⁺, RCC⁺, vimentin⁺, and AMACR⁺) and ultrastructural (abundant long brush border microvilli) characteristics of proximal renal tubules. In few cells, the microvilli were shorter and sparse with cytoplasmic interdigitation analogous to intercalated cells of the collecting ducts. Focal positivity for BerEP4 (a marker preferentially expressed in distal renal tubules) was also noted. The major differential diagnostic considerations are oncocytoma, multilocular cystic renal cell carcinoma, and cystic nephroma/mixed epithelial and stromal tumor of the kidney. TCCK seems to have a favorable prognosis. In the current series, none of the patients had local recurrence or metastatic disease.     

Renal epithelial neoplasms: the diagnostic implications of electron microscopic study in 55 cases

Several unsettled histogenetic, nosologic and diagnostic considerations for renal epithelial tumors may have ultrastructural ramifications. Yet, a comprehensive electron microscopic study of renal epithelial neoplasms, in light of the recent classification, is not available. The ultrastructural findings from fifty-five renal epithelial neoplasms [31 clear cell renal cell carcinomas (RCC), 11 papillary RCC, 5 chromophobe RCC, 3 sarcomatoid RCC and 5 oncocytomas] were correlated with their light microscopic appearance. Clear cell RCC showed long microvilli similar to the brush border of the normal proximal tubules, with abundant cytoplasmic lipid and glycogen. Papillary RCC showed variably sized microvilli, and small amounts of cytoplasmic lipid, but no glycogen. Chromophobe RCC showed many cytoplasmic vesicles and abnormal mitochondria, with rare short and stubby microvilli. Renal oncocytoma showed many mitochondria with a few vesicles in the apical portion of the cytoplasm and rare short and stubby microvilli. The eosinophilic cell variants of clear cell RCC, papillary RCC and chromophobe RCC showed ultrastructural features similar to those of their respective prototypes, except for an increased numbers of mitochondria in the cytoplasm. One sarcomatoid clear cell RCC showed skeletal muscle differentiation. Two types of cytoplasmic inclusions, i.e. hyaline globules and granules similar to those in the Paneth cells (PC-like granules) were identified only in clear cell RCC, which displayed distinctive ultrastructural features. The current EM study demonstrates distinctive ultrastructural features of renal epithelial neoplasms. The findings lend additional support to the current classification of the pertinent tumor types, facilitate the differential diagnoses, and provide insights into the possible histogenesis of renal epithelial neoplasms.     

Multilocular cystic renal cell carcinoma

Multilocular cystic renal cell carcinoma (MCRCC) appears to be a distinct subtype of renal cell carcinoma with characteristic gross and microscopic features. The authors' ten-year experience (1977-1987) included six cases of MCRCC that were followed for a minimum of two years, with neither recurrence nor metastasis observed in any of the cases. During this period, there were 855 urologic procedures for the upper urinary tract, with 256 neoplasms or cysts identified. These included 32 simple cysts, 41 transitional cell carcinomas, 133 renal cell carcinomas, 17 papillary renal cell carcinomas, and 33 miscellaneous tumors. Histologically, the MCRCCs were well-demarcated multicystic lesions containing variably sized aggregates of neoplastic clear cells showing grade 1 nuclear features and little or no mitotic activity. The cyst walls were densely fibrotic, and the lining was often devoid of epithelium. Flow-cytometric analysis performed in five of the six cases with the use of paraffin-embedded tissue showed the tumors to be diploid in all instances, with low proliferative activity. The authors believe that this tumor is a low-grade variant of renal cell carcinoma and should be studied further to determine appropriate therapy.     

Hereditary and Sporadic Papillary Renal Carcinomas with c-met Mutations Share a Distinct Morphological Phenotype

Germline mutations of c-met oncogene at 7q31 have been detected in patients with hereditary papillary renal cell carcinoma. In addition, c-met mutations were shown to play a role in 13% of patients with papillary renal cell carcinoma and no family history of renal tumors. The histopathology of papillary renal cell carcinoma with c-met mutations has not been previously described. We analyzed the histopathology of 103 bilateral archival papillary renal cell carcinomas and 4 metastases in 29 patients from 6 hereditary papillary renal cell carcinoma families with germline c-met mutations and 6 papillary renal cell carcinomas with c-met mutations from 5 patients with no family history of renal tumors. Twenty-five sporadic renal tumors with prominent papillary architecture and without somatic c-met mutations were evaluated for comparison. All papillary renal cell carcinomas with c-met mutations were 75 to 100% papillary/tubulopapillary in architecture and showed chromophil basophilic, papillary renal cell carcinoma type 1 histology. Fuhrman nuclear grade 1-2 was seen in tumors from 23 patients, and nuclear grade 3 was observed focally in 8 patients. Seventeen patients had multiple papillary adenomas and microscopic papillary lesions in the surrounding renal parenchyma. Clear cells with intracytoplasmic lipid and glycogen were focally present in tumors of 94% papillary renal cell carcinoma patients. Clear cells of papillary renal cell carcinoma had small basophilic nuclei, and clear cell areas lacked a fine vascular network characteristic of conventional (clear) cell renal cell carcinoma. We conclude that papillary renal cell carcinoma patients with c-met mutations develop multiple, bilateral, papillary macroscopic and microscopic renal lesions. Renal tumors with c-met genotype show a distinctive papillary renal cell carcinoma type 1 phenotype and are genetically and histologically different from renal tumors seen in other hereditary renal syndromes and most sporadic renal tumors with papillary architecture. Although all hereditary and sporadic papillary renal cell carcinomas with c-met mutations share papillary renal cell carcinoma type 1 histology, not all type 1 sporadic papillary renal cell carcinomas harbor c-met mutations.     

Recent classification of renal epithelial tumors

The recent classification of renal tumors is based on genetic evidence as well as on histologic features. Malignant tumor includes clear cell renal carcinoma (RCC), multilocular cystic RCC, papillary RCC, chromophobe RCC, carcinoma of the collecting duct of Bellini, renal carcinoma associated with Xp11.2 translocations/TFE3 gene fusions and mucinous tubular and spindle cell carcinoma. Benign tumor is subdivided into papillary adenoma, renal oncocytoma and metanephric adenoma. Recently, new disease entities such as acquired cystic disease-associated RCC, clear cell papillary RCC and renal carcinoma with t(6;11)(p21:q12) have been discovered. In this article, we briefly review and introduce the clinical, morphological and genetic features of these tumor entities.     

The leiomyomatous stroma in renal cell carcinomas is polyclonal and not part of the neoplastic process

Some renal epithelial neoplasms, such as renal angiomyoadenomatous tumor, clear cell papillary renal cell carcinoma and renal cell carcinoma with smooth muscle stroma, contain a variably prominent smooth muscle stromal component. Whether or not this leiomyomatous stroma is part of the neoplastic proliferation has not been firmly established. We studied the clonality status of 14 renal cell carcinomas with a prominent smooth muscle stromal component (four renal angiomyoadenomatous tumors/clear cell papillary carcinomas, five clear cell carcinomas, two papillary carcinomas, and three renal cell carcinomas with smooth muscle rich stroma) using the human androgen receptor assay (HUMARA). We found the leiomyomatous stromal component in all analyzable (8/14) cases to be polyclonal and therefore reactive rather than neoplastic. Based on morphological observations, we propose that the non-neoplastic leiomyomatous stromal component is likely derived from smooth muscle cells of large caliber veins located at the peripheral capsular region or within the collagenous septae of the tumors.     

Expression of prostate-specific membrane antigen in renal cortical tumors.

Prostate-specific membrane antigen is a type II membrane glycoprotein that is expressed in benign and neoplastic prostatic tissue and has been recently shown to be also expressed in the neovasculature of various solid malignant tumors including renal cell carcinoma. Renal cell carcinoma is a heterogeneous group of tumors with distinct morphologic and genetic characteristics and clinical behaviors. We performed immunohistochemical studies on formalin-fixed, paraffin-embedded archival material from 75 nephrectomies, using antibodies 13D6 against prostate-specific membrane antigen and CD31 against endothelial cells. The study included 30 clear cell renal cell carcinomas, and 15 of each of papillary and chromophobe renal cell carcinoma and oncocytoma. The extent and intensity of staining were assessed semiquantitatively. In all cases, immunoreactivity was detected only in the tumor-associated neovasculature and not in tumor cells. Clear cell renal cell carcinoma showed the most diffuse staining pattern, where 24/30 cases or 80% had >50% reactive vessels, followed by chromophobe renal cell carcinoma (9/15; 60%) and oncocytoma (5/15, 33%). No diffuse staining was detected in any of the papillary renal cell carcinomas and only focal staining was detected in 11 cases (11/15; 73%). Staining intensity was the strongest in clear cell renal cell carcinoma (25/30; 83%) followed by chromophobe renal cell carcinoma (9/15; 60%), oncocytoma (8/15, 53%) and papillary renal cell carcinoma (5/15; 33%). In summary, prostate-specific membrane antigen is expressed in tumor-associated neovasculature of the majority of renal cortical tumors and is most diffusely and intensely expressed in clear cell renal cell carcinoma and least in papillary renal cell carcinoma. The differences in the expression of prostate-specific membrane antigen in renal cell carcinoma subtypes provide further evidence of the biological diversity of these tumors, and diagnostic and therapeutic applications of such expression can be expanded to include subtypes of renal cell carcinoma.     

Clear cell papillary renal cell carcinoma: a review

The disease concept of clear cell (tubulo) papillary renal cell carcinoma (CCP-RCC) as a distinct subtype of renal cell carcinoma has been recently established. First described in the setting of end stage renal disease, this tumor type is more frequently recognized and encountered in a sporadic setting. In this article, we provide an overview of the recent understanding of this tumor. Macroscopically, tumors are well circumscribed with well-developed tumor capsule. Histologically, the tumor cells are cuboidal to low columnar cell with clear cytoplasm and papillary and tubulo-papillary configuration. Immunohistochemically, tumor cells generally show diffuse expression for cytokeratin 7, CA9 (cup-shaped pattern), HIF-1, GLUT-1 and high molecular weight cytokeratin, but negative for AMACR, RCC Ma and TFE3. CD10 is negative or focally positive in most tumors. Genetically, this tumor has no characteristics of clear cell RCC or papillary RCC. Prognostically, patients with CCP-RCC behave in an indolent fashion in all previously reported cases. In conclusion, although this tumor has been integrated into recent International Society of Urologic Pathology Classification of renal neoplasia, both aspects of disease concept and clinical behavior are yet to be fully elucidated. Further publications of large cohorts of patients will truly help understand the biologic potential and the molecular underpinnings of this tumor type.     

The 2012 ISUP Vancouver and 2016 WHO classification of adult renal tumors: changes for common renal tumors

In the past decade, the histological classification of renal neoplasia has undergone significant changes. Many new entities with distinct clinical, pathological and genetic features have been identified. In addition, common and established tumor entities have been further refined with regard to their pathological and genetic features. These changes have been incorporated in the 2012 International Society of Urological Pathology Vancouver classification and also in the 2016 World Health Organization classification. This article will focus on the new discoveries of clinical, pathological and molecular characteristics of the common renal tumors, including clear cell renal cell carcinoma, multilocular cystic renal neoplasm of low malignant potential, papillary renal cell carcinoma, chromophobe renal cell carcinoma, mucinous tubular and spindle cell renal cell carcinoma, collecting duct carcinoma, renal medullary carcinoma, papillary adenoma, oncocytoma, metanephric tumors, angiomyolipoma, and mixed epithelial and stromal tumor.