chromophobe renal cell tumor: An integrated genetic and epigenetic characterization of a case

Accepted Manuscript Hybrid oncocytic/chromophobe renal cell tumor: An integrated genetic and epigenetic characterization of a case

A. Pires-Luis, D. Montezuma, J. Vieira, J. Ramalho-Carvalho, C. Santos, M. Teixeira, C. Jerónimo, R. Henrique PII: DOI: Reference:

S0014-4800(18)30154-0 doi:10.1016/j.yexmp.2018.10.008 YEXMP 4186

To appear in:

Experimental and Molecular Pathology

Received date: Revised date: Accepted date:

4 April 2018 9 August 2018 17 October 2018

Please cite this article as: A. Pires-Luis, D. Montezuma, J. Vieira, J. Ramalho-Carvalho, C. Santos, M. Teixeira, C. Jerónimo, R. Henrique , Hybrid oncocytic/chromophobe renal cell tumor: An integrated genetic and epigenetic characterization of a case. Yexmp (2018), doi:10.1016/j.yexmp.2018.10.008

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ACCEPTED MANUSCRIPT

Hybrid oncocytic / chromophobe renal cell tumor: an integrated genetic and epigenetic characterization of a case Pires-Luis A.1,2,3* , Montezuma D.1* , Vieira J.4 , Ramalho-Carvalho J.2 , Santos C.4 , Teixeira M.4,5 , Jerónimo C.2,5§, Henrique R.1,2,5§

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Department of Pathology, Portuguese Oncology Institute of Porto Cancer Biology & Epigenetics Group, Research Center, Portuguese Oncology Institute of Porto 3 Department of Microscopy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Portugal 4 Department of Genetics, Portuguese Oncology Institute of Porto 5 Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Portugal

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Corresponding author Rui Henrique, M.D., Ph.D. Department of Pathology Portuguese Oncology Institute of Porto Rua Dr. Antonio Bernardino de Almeida 4200-072 Porto Portugal E-mail: [email protected] Phone: +351 225084000 (ext. 7925) Fax: +351 225084199

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* These authors contributed equally to this work § Joint senior authors

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Conflict of Interest statement The authors declare they have no conflict of interest. Financial Disclosure statement This work was supported by a grant from Research Center of Portuguese Oncology Institute of Porto (PI 74-CI-IPOP-19-2016). ASP-L and JRC were supported by FCT Fundação para a Ciência e a Tecnologia fellowships (SFRH/SINTD/94217/2013 and SFRH/BD/71293/2010, respectively).

ACCEPTED MANUSCRIPT Abstract Introduction. Hybrid oncocytic/chromophobe tumor (HOCT) is a renal cell neoplasm displaying overlapping cellular and architectural features of both renal oncocytoma (RO) and chromophobe renal cell carcinoma (chRCC). It has been described in the context of oncocytosis, Birt-Hogg-Dubé syndrome, and also sporadically. Thus far,

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HOCT immunohischemical profile and cytogenetic alterations have been reported, but

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expression, comparing it to sporadic RO and chRCC.

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not epigenetic alterations. Herein, we characterize a HOCT case, including microRNA

Methods. An HOCT was entirely submitted. Representative paraffin blocks were

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selected for histochemical, immunohistochemical and FISH analyses. MicroRNAs were extracted from the two components separately and selected microRNA expression was

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performed.

Results. This 4cm HOCT, from a 69 year-old female, was composed mainly by

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oncocytic cells with an insular distribution (RO-like) and areas of larger clarified cells (chRCC-like). The two areas displayed different features: RO-like areas showed colloidal iron staining,

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negative

multifocal CD15, negative CK7, focal multiple

tetrasomies, and higher miR21 expression; chRCC-like areas showed colloidal iron staining

with

moderate

intensity,

focal CD15

and

CK7,

no

numeric

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diffuse

chromosomic alterations, and higher miR141 and miR200b expression. Conclusion. microRNA expression in the two HOCT components is similar to its sporadic tumors counterparts. Morphologic, immunohistochemical, cytogenetic and epigenetic data on this case suggest either two independent pathogenic pathways or an early pathogenic divergence for RO-like and chRCC-like components of HOCT.

ACCEPTED MANUSCRIPT Key words Kidney cancer; hybrid oncocytic-chromophobe renal cell tumor; HOCT; FISH; microRNA

Abbreviations oncocytic/chromophobe

tumor;

RO: renal oncocytoma; chRCC:

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chromophobe renal cell carcinoma; BHD: Birt-Hogg-Dubé;

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HOCT: hybrid

ACCEPTED MANUSCRIPT Introduction Hybrid oncocytic/chromophobe tumor (HOCT) is a renal cell neoplasm comprising cellular and architectural features of both renal oncocytoma (RO) and chromophobe renal cell carcinoma (chRCC) (Mai et al., 2005), first described in association with renal oncocytosis (Tickoo et al., 1999) and Birt-Hogg-Dubé (BHD) syndrome (Pavlovich et

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al., 2002). Since then, more than fifty sporadic cases have been reported (Delongchamps

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et al., 2009; Mai et al., 2005; Petersson et al., 2010; Pote et al., 2013; Waldert et al.,

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2010).

Because HOCT present overlapping morphological features with chRCC and RO, it has

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been suggested that it might be part of a tumor spectrum between chRCC and RO (Mai et al., 2005; Waldert et al., 2010). Although this entity is considered a subtype of

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chRCC in the latest 2016 WHO classification of renal cell tumors (Moch H, 2016), some authors argue that HOCT is not a mere chRCC variant, based on morphological

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and cytogenetic data (Petersson et al., 2010), whilst others suggest that HOCT is more likely an oncocytoma variant (Pote et al., 2013).

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Morphologic features of HOCT mostly comprise distinct typical RO and typical chRCC areas admixed within a single neoplasm, a RO background with scattered chRCC cells,

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or cells with oncocytic cytoplasm arranged in a solid-alveolar pattern presenting some overlapping cytologic and histochemical features of RO and chRCC cells. Although the classically described pattern in tumors from BHD and oncocytosis patients was chRCClike areas admixed in predominant RO-like areas with a gradual transition between them (Pavlovich et al., 2002; Tickoo et al., 1999), this pattern was also observed in some sporadic cases (Delongchamps et al., 2009; Mai et al., 2005; Petersson et al., 2010). Colloidal iron staining pattern is diverse, described as negative or apical staining in ROlike areas and weak to moderate or diffuse in chRCC-like areas (Delongchamps et al.,

ACCEPTED MANUSCRIPT 2009; Mai et al., 2005). The proportion of cells immunoreactive for CK7 in each HOCT is variable (Pote et al., 2013; Waldert et al., 2010) and rare cases were found negative (Mai et al., 2005; Petersson et al., 2010). Interestingly, the most frequently described cytogenetic alterations in HOCT are chromosome 9 and 20 monosomy, and chromosome 10, 21 and 22 polysomy (Petersson et al., 2010), which are distinct from

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those observed in either chRCC or oncocytoma (Vieira et al., 2010). Although the

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immunoexpression and cytogenetic profile has been already well characterized, specific

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epigenetic alterations have not been reported for HOCT, thus far.

We have recently shown that expression levels of a miRNA panel significantly differ

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between RO and chRCC, allowing for accurate discrimination among these renal cell tumor subtypes (Silva-Santos et al., 2013). Having identified a case of HOCT in the

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diagnostic routine, with typical morphological, histochemical and immunohistochemical features, we aimed to characterize it at cytogenetic and epigenetic (miRNA) levels

Methods Sample collection

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enabling a more comprehensive comparison with RO and chRCC.

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Tissue fragments for routine pathological evaluation were selected, fixed in buffered formalin and paraffin embedded. The entire kidney tumor was submitted, and the corresponding

hematoxylin-eosin

stained

sections

were

evaluated

for

tumor

classification and staging. A representative paraffin block was further selected for histochemical, immunohistochemical and FISH analyses, as well as for microRNA extraction. Relevant clinical data were collected from the patient chart. This study was approved by the Ethics Committee of Portuguese Oncology Institute of Porto.

ACCEPTED MANUSCRIPT Histochemistry and immunohistochemistry Colloidal iron (Hale) staining was performed in 4µm-thick sections according to routine protocol (Jones ML, 2008). Immunostaining was also performed in 4µm-thick sections, with appropriate tissue controls, using the BrightVision Poly-HRP-Anti Ms/Rb/RtIgG biotin-free, one component, ready to use system (Immunologis, The Netherlands). available

primary

antibodies

against

CK7

(OV-TL12/30;

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Commercially

1:150;

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Novocastra - Leica, UK), CD15 (Carb3; Ready to Use; Dako, Denmark) were used.

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A qualitative evaluation of colloidal iron (Hale) staining, CD15 and CK7 expression

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was performed by light microscopy at x400 magnification.

FLCN mutational status

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Mutation screening of the FLCN gene was performed by Next Generation Sequencing as previously described (Paulo et al., 2017). Multiplex Ligation-dependent Probe

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Amplification (MLPA) (MRC-Holland, Amsterdam, Netherlands) was used to detect

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FLCN large genomic rearrangements, according to the manufacturer’s instructions.

Fluorescence in situ hybridization (FISH)

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FISH analysis was performed with probes for chromosomes 1, 9, 10, 11, 13, 14, 17, 20 and 21. Commercial probes ON SRD (1p36) / SE 1(1qh) (Kreatech/Leicabiosystems); Vysis CDKN2A / CEP 9 FISH Probe Kit, Vysis LSI MLL Dual Color, Break Apart Rearrangement Probe, Vysis LSI 13 (RB1) 13q14 Spectrum Green Probe, Vysis LSI IGH Dual Color, Break Apart Rearrangement Probe, CEP 17 (D17Z1) Aqua, Vysis LSI D20S108 Orange, Vysis LSI 21 Orange, Vysis EWSR1 Break Apart FISH Probe Kit (Vysis/Abbott) and with ZytoLight ® SPEC WT1 Dual Color Break Apart Probe (Zytovision). FISH was performed on 4µm sections in SuperFrost Plus Adhesion slides.

ACCEPTED MANUSCRIPT Specimens and probes were placed in a Hybrite denaturation/hybridization system and co-denaturated at 80ºC for 8 minutes. Hybridization took place for 16h at 37ºC, followed by post-hybridization washes at room temperature, after which slides were counterstained with DAPI (Vector Laboratories, Burlingame, California, USA) and fluorescent images corresponding to DAPI, SpectrumGreen and SpectrumOrange were

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sequentially captured with a Cohu 4900 CCD camera, with the use of an automated

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filter wheel coupled to a Zeiss Axioplan fluorescence microscope (Zeiss, Oberkochen,

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Germany) and a CytoVision system (Applied Imaging, Santa Clara, California, USA).

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RNA extraction, reverse transcription and quantitative real-time PCR Eight consecutive 10µm formalin-fixed paraffin embedded (FFPE) representative tissue

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sections were taken. Oncocytoma and ChRCC components were identified and RNA was isolated separately from each component with Recover AllTM Total Nucleic Acid

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Isolation Kit (Life Technologies, Carlsbad, CA, USA) according with recommended protocol. Reverse transcription (RT) was performed using TaqMan MicroRNA Reverse

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Transcription Kit (Applied Biosystems, Foster City, CA, USA). Quantitative RT–PCR was performed using TaqMan Small RNA Assays (Applied Biosystems) in a 7500

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Real-Time PCR system (Applied Biosystems), according with the manufacturer’s protocol. Expression levels of three selected miRNAs - miR-21, miR-141 and miR200b (miR-21: Tm000397; miR-141: Tm000483; and miR-200b: Tm002251) - previously shown to accurately discriminate among different renal cell tumors subtypes, namely RO from chRCC (Silva-Santos et al., 2013), were assessed.

Results

ACCEPTED MANUSCRIPT Case description An asymptomatic 69 year-old female was referred to our institution due to a left renal mass incidentally discovered during abdominal ultrasound examination. Hypertension and dyslipidemia, currently under treatment, were the only known co-morbidities. No personal or familial history of neoplasia or genetic diseases was disclosed. abdominal

computed

tomography

(CT)

revealed

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Contrast-enhanced

a

4cm

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hypervascular lesion in the lower pole of the left kidney, and pre-operative

patient was submitted to left renal nephrectomy.

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investigations showed no relevant alterations. Kidney biopsy was not performed and the

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Macroscopically, a 4cm solid tumor was identified, with well-defined expansive borders and a tan-yellowish cut surface, with focal hemorrhagic areas.

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On microscopic observation, two distinct areas were identified (Figure 1A). Most of the tumor was composed of oncocytic cells, with granular cytoplasm and round nuclei,

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focally with a perinuclear halo, in an insular distribution, with edematous stroma in some regions – RO-like area (Figure 1B). In the periphery and merging with the

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previously described component, a small area of tumor was composed of large polygonal cells, with well defined cell membranes, clarified or eosinophilic cytoplasm,

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and round to oval nuclei – chRCC-like area (Figure 1C). Some binucleated cells were also identified. Necrosis was not observed, nor raisinoid nuclei in the chRCC-like area. These two areas displayed distinct histochemical and immunohistochemical profile (Figure 2). RO-like areas were negative for Hale staining and negative CK7 expression, displaying strong, multifocal, CD15 expression, whereas chRCC-like areas showed moderate diffuse staining with Hale, and focal CD15 and CK7 expression. Genetic analysis for Birt-Hogg-Dubé syndrome was performed, and no germline mutations were found in FCLN gene.

ACCEPTED MANUSCRIPT The patient is alive and with no evidence of disease after 25 months of follow-up.

FISH analysis Using FISH methodology, the most frequent cytogenetic alterations in oncocytomas (namely 1p and 14q deletion and also for 11q gain) and chRCC (including loss of

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chromosomes 1, 2, 10, 13, 17 and 21) (Brunelli et al., 2005), as well as cytogenetic

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alterations previously described in HOCT (monosomy of chromosome 9 and 20 and

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polysomy of chromosomes 10 and, 21 and 22) were assessed (Petersson et al., 2010; Vieira et al., 2010).

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In the RO-like area, FISH analysis revealed a population with tetrasomy of all chromosomes analyzed, with no 1p or 14q deletion nor 11q gain; and in the

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chromophobe-like area, two copies of all the chromosomes analyzed were found.

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microRNA analysis

The 3 miRNAs were tested separately in each HOCT area. Higher miR-141 and miR-

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200b expression was found in the chRCC-like area with a relative fold difference of 2.6 and 1.2, respectively, whereas miR-21 expression was higher in the RO-like area with a

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relative fold difference of 1.6 (Table 1). These results are in line with those reported for sporadic chRCC and RO (Silva-Santos et al., 2013).

Discussion Hybrid oncocytoma-chromophobe renal cell tumor is a rare entity, accounting for up to 2% of sporadic tumors of the chRCC/HOCT/RO group in the largest reported series (Petersson et al., 2010; Pote et al., 2013), and 11% (Delongchamps et al., 2009; Mai et al., 2005) to 17.5% (Waldert et al., 2010) in smaller series. In BHD patients, however,

ACCEPTED MANUSCRIPT HOCT is the most frequent renal tumor subtype (Pavlovich et al., 2002). The differential diagnosis with oncocytoma and chRCC, mainly its eosinophilic variant, might be challenging, due to the overlapping phenotype of these entities. Indeed, HOCT might present cells with abundant eosinophilic granular cytoplasm similar to those of RO, sometimes with a perinuclear halo and disposed in an alveolar pattern as in

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eosinophilic chRCC; or be formed mainly by a RO-like component which merges with

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a chRCC-like component (Petersson et al., 2010; Pote et al., 2013). Colloidal iron

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(Hale) stain and immunohistochemistry (CK7, CD15) might be helpful in routine diagnosis of HOCT.

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In the case here described, most of the tumor was composed by oncocytic cells, predominantly colloidal iron negative, with rare cells displaying apical staining, CK7

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negative and strong multifocal CD15 immunoexpression, similar to sporadic RO. The area with larger clarified cells showed diffuse and moderate intensity colloidal iron

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staining. Additionally, most cells were CD15 and CK7 negative, and only few cells displayed a weak to moderate expression for these markers. This is in line with previous

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reports of positive colloidal iron staining in chRCC-like areas, although of weak to moderate intensity (Delongchamps et al., 2009; Mai et al., 2005). Most sporadic chRCC

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are CD15 negative, and the weak intensity CD15 staining in some chRCC-like cells might correspond to an overlapping RO/chRCC immunophenotype, as well as the CK7 positivity in scattered isolated chRCC-cells, more similar to the sporadic RO staining pattern than to the diffuse staining frequently observed in sporadic chRCC. However, up to 15-18% of sporadic chRCC might be CK7 negative (Kryvenko et al., 2014; Liu et al., 2007), as well as some HOCT (Mai et al., 2005; Petersson et al., 2010). Interestingly, we found a different genetic pattern in the RO-like and chRCC-like areas, i.e., multiple tetrasomies and no alterations of all chromosomes analyzed, respectively.

ACCEPTED MANUSCRIPT Although genome tetrasomy in late interphase is a known limitation of FISH analysis, in the analyzed sample this does not seem to be the case, as the proportion of proliferating cells is very low and some binucleated cells were observed, which might account for some of the tetrasomic cells identified by FISH. Interestingly, no differences between the two HOCT components have been found in a previous study,

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using comparative genomic hybridization (CGH) (Pote et al., 2013). Although CGH

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does not detect balanced translocations, it would have detected the chromosome gains

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that we identified by FISH, as we have demonstrated in a previous publication (Petersson et al., 2010; Vieira et al., 2010). Moreover, these alterations are distinct from

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the cytogenetic abnormalities typically found in the sporadic tumors: 1p and 14q deletion and 11q gain in RO and loss of chromosomes 1, 2, 10, 13, 17 and 21 in chRCC

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(Brunelli et al., 2005). Finally, our case did not disclose the cytogenetic alterations previously described in HOCT, including chromosome 6, 9 and 20 monosomy, and

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chromosome 10 and, 21 and 22 polysomy (Petersson et al., 2010). Nevertheless, it should be noted that sporadic oncocytomas and a minority of chRCC might present

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normal karyotype (Brunelli et al., 2005), and that no chromosomal imbalances were detected by CGH in some HOCT (Pote et al., 2013). Thus, our findings extend the

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spectrum of HOCT cytogenetic profile, similar to oncocytomas and chRCC with normal karyotype, as well as multiple tetrasomies in the RO-like area, alterations that might be found in HOCT and emphasize the heterogeneous character of these neoplasms. Although genetic features of HOCT have been characterized, its epigenetic profile is, to the best of our knowledge, unknown. Because we have previously found that RO and chRCC disclose a different miRNA profile (Silva-Santos et al., 2013), we assessed the expression of the selectd miRNA panel in the two different morphological components of our tumor. Remarkably, higher miR-141 and miR200b relative expression were

ACCEPTED MANUSCRIPT found in the chRCC-like component, and higher miR-21 was found in the RO-like component, in line with our previous observations in sporadic chRCC compared to sporadic RO (Silva-Santos et al., 2013). Thus, a close correlation between morphology and miRNA expression profile was disclosed, especially for miR-21 and miR-141, which displayed the highest fold variation between the two components.

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Taken together, our data strongly suggest that HOCT bearing distinct RO-like and

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chRCC-like components result from divergent cell differentiation, that probably occurs

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at a very early step of the tumorigenic process. A “collision” between two distinct tumors might also explain our findings but it seems less likely owing to the

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intermingling of the two components. Furthermore, these data further support the concept that HOCT represent a truly distinct disease entity, as some alterations found in

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the discreet components are similar to those of its sporadic counterparts (e.g., microRNA expression), whilst others differ significantly (e.g., cytogenetic features).

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Finally, considering our results and published reports on genetic features of HOCT, considerable heterogeneity is apparent and might indicate different tumor subsets. A

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more extensive genetic and epigenetic characterization of a larger number of HOCT might provide the necessary evidence for the recognition of this distinct renal cell tumor

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type.

Funding / Acknowledgments This work was supported by a grant from Research Center of Portuguese Oncology Institute of Porto (PI 74-CI-IPOP-19-2016). ASP-L and JRC were supported by FCT Fundação para a Ciência e a Tecnologia fellowships (SFRH/SINTD/94217/2013 and SFRH/BD/71293/2010, respectively).

Conflict of Interests The authors declare they have no conflict of interest.

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ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT References

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Brunelli, M., et al., 2005. Eosinophilic and classic chromophobe renal cell carcinomas have similar frequent losses of multiple chromosomes from among chromosomes 1, 2, 6, 10, and 17, and this pattern of genetic abnormality is not present in renal oncocytoma. Mod Pathol. 18, 161-9. Delongchamps, N. B., et al., 2009. Hybrid tumour 'oncocytoma-chromophobe renal cell carcinoma' of the kidney: a report of seven sporadic cases. BJU Int. 103, 1381-4. Jones ML, B. J., Gamble M, Connective Tissues and Stains. In: G. M. Bancroft JD, (Ed.), Theory and Practice of Histological Techniques. Churchill Livingstone Elsevier, Philadelphia, 2008, pp. 175-176 Kryvenko, O. N., et al., 2014. Diagnostic approach to eosinophilic renal neoplasms. Arch Pathol Lab Med. 138, 1531-41. Liu, L., et al., 2007. Immunohistochemical analysis of chromophobe renal cell carcinoma, renal oncocytoma, and clear cell carcinoma: an optimal and practical panel for differential diagnosis. Arch Pathol Lab Med. 131, 1290-7. Mai, K. T., et al., 2005. Hybrid chromophobe renal cell neoplasm. Pathol Res Pract. 201, 385-9. Moch H, H. P., Ulbright TM, Reuter VE (Eds), 2016. WHO Classification of Tumours of the Urinary System and Male Genital Organs. International Agency for Research on Cancer, Lyon. Paulo, P., et al., 2017. Validation of a Next-Generation Sequencing Pipeline for the Molecular Diagnosis of Multiple Inherited Cancer Predisposing Syndromes. J Mol Diagn. 19, 502513. Pavlovich, C. P., et al., 2002. Renal tumors in the Birt-Hogg-Dube syndrome. Am J Surg Pathol. 26, 1542-52. Petersson, F., et al., 2010. Sporadic hybrid oncocytic/chromophobe tumor of the kidney: a clinicopathologic, histomorphologic, immunohistochemical, ultrastructural, and molecular cytogenetic study of 14 cases. Virchows Arch. 456, 355-65. Pote, N., et al., 2013. Hybrid oncocytic/chromophobe renal cell tumours do not display genomic features of chromophobe renal cell carcinomas. Virchows Arch. 462, 633-8. Silva-Santos, R. M., et al., 2013. MicroRNA profile: a promising ancillary tool for accurate renal cell tumour diagnosis. Br J Cancer. 109, 2646-53. Tickoo, S. K., et al., 1999. Renal oncocytosis: a morphologic study of fourteen cases. Am J Surg Pathol. 23, 1094-101. Vieira, J., et al., 2010. Feasibility of differential diagnosis of kidney tumors by comparative genomic hybridization of fine needle aspiration biopsies. Genes Chromosomes Cancer. 49, 935-47. Waldert, M., et al., 2010. Hybrid renal cell carcinomas containing histopathologic features of chromophobe renal cell carcinomas and oncocytomas have excellent oncologic outcomes. Eur Urol. 57, 661-5.

ACCEPTED MANUSCRIPT FIGURE CAPTIONS

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Figure 1. Title: HOCT – histology. Description: Two distinct areas were identified in this tumor (1A): a RO-like area composed by bland oncocytic cells with insular architecture (1B), and a chRCC-like area composed of large clear cells and smaller eosinophilic cells with irregular nuclei (1C).

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Figure 1 and Figure 2 – color: online only

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Figure 2. Title: HOCT – histochemical and immunohistochemical features. Description: Histochemical and immunohistochemical stains in the RO-like (2A, 2C, 2E) and chRCC-like (2B, 2D, 2F) areas. Colloidal iron (Hale) was negative in RO-like areas (2A) and positive in chRCC-like areas (2B); a strong multifocal CD15 expression was noted in RO-like areas (2C), whereas in chRCC-like areas (2D) it was focal; CK7 was negative in RO-like areas (2E) and focally positive in chRCC areas (2F).

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TABLES Table 1. miRNAs expression levels for distinct areas in HOCT. HOCT case RO-like area

chRCC-like area

76.3 66.0 59.3

46.9 173.5 72.1

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miR-21 miR-141 miR-200b

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HOCT: hybrid oncocytoma-chromophobe renal cell tumor; RO: renal oncocytoma; chRCC: chromophobe renal cell carcinoma; miRNA: micro RNA; miRNA expression level = miRNA expression mean quantity/((RNU48 mean quantity+RNU6B mean quantity)/2).

ACCEPTED MANUSCRIPT Hybrid oncocytic / chromophobe renal cell tumor: an integrated genetic and epigenetic characterization of a case - HIGHLIGHTS

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HOCT displays overlapping features of oncocytoma and chromophobe carcinoma. This case has different features in each oncocytoma and chromophobe-like areas. Oncocytoma-like: - Hale stain, ++CD15, -CK7, multiple tetrasomies. Chromophobe like: + Hale stain, +CD15, ++CK7, no numeric chromosomic alterations. miR21 higher in oncocytoma-like; miR141 and miR200b in chromophobe-like.

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