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Kanakaraj J, Chang J, Hampton LJ, Smith SC. The New WHO Category of "Molecularly Defined Renal Carcinomas": Clinical and Diagnostic Features and Management Implications. Urol Oncol 2024; 42:211-219. [PMID: 38519377 DOI: 10.1016/j.urolonc.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/27/2024] [Accepted: 02/12/2024] [Indexed: 03/24/2024]
Abstract
The evolution of classification of renal tumors has been impacted since the turn of the millennium by rapid progress in histopathology, immunohistochemistry, and molecular genetics. Together, these features have enabled firm recognition of specific, classic types of renal cell carcinomas, such as clear cell renal cell carcinoma, that in current practice trigger histologic-type specific management and treatment protocols. Now, the fifth Edition World Health Classification's new category of "Molecularly defined renal carcinomas" changes the paradigm, defining a total of seven entities based specifically on their fundamental molecular underpinnings. These tumors, which include TFE3-rearranged, TFEB-altered, ELOC-mutated, fumarate hydratase-deficient, succinate dehydrogenase-deficient, ALK-rearranged, and SMARCB1-deficient renal medullary carcinoma, encompass a wide clinical and histopathologic phenotypic spectrum of tumors. Already, important management aspects are apparent for several of these entities, while emerging therapeutic angles are coming into view. A brief, clinically-oriented introduction of the entities in this new category, focusing on relevant diagnostic, molecular, and management aspects, is the subject of this review.
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Affiliation(s)
- Jonathan Kanakaraj
- Department of Pathology, Virginia Commonwealth University School of Medicine, Richmond, VA
| | - Justin Chang
- Department of Pathology, Virginia Commonwealth University School of Medicine, Richmond, VA
| | - Lance J Hampton
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, VA; Department of Pathology, Richmond Veterans Affairs Medical Center, Richmond, VA; VCU Massey Comprehensive Cancer Center, Richmond, VA
| | - Steven Christopher Smith
- Department of Pathology, Virginia Commonwealth University School of Medicine, Richmond, VA; Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, VA; Department of Pathology, Richmond Veterans Affairs Medical Center, Richmond, VA; VCU Massey Comprehensive Cancer Center, Richmond, VA.
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Sanguedolce F, Mazzucchelli R, Falagario UG, Cormio A, Zanelli M, Palicelli A, Zizzo M, Eccher A, Brunelli M, Galosi AB, Carrieri G, Cormio L. Diagnostic Biomarkers in Renal Cell Tumors According to the Latest WHO Classification: A Focus on Selected New Entities. Cancers (Basel) 2024; 16:1856. [PMID: 38791935 PMCID: PMC11120103 DOI: 10.3390/cancers16101856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Revised: 05/02/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
The fifth edition of the World Health Organization (WHO) classification for urogenital tumors, released in 2022, introduces some novelties in the chapter on renal epithelial tumors compared to the previous 2016 classification. Significant changes include the recognition of new disease entities and adjustments in the nomenclature for certain pathologies. Notably, each tumor entity now includes minimum essential and desirable criteria for reliable diagnosis. This classification highlights the importance of biological and molecular characterization alongside traditional cytological and architectural features. In this view, immunophenotyping through immunohistochemistry (IHC) plays a crucial role in bridging morphology and genetics. This article aims to present and discuss the role of key immunohistochemical markers that support the diagnosis of new entities recognized in the WHO classification, focusing on critical topics associated with single markers, in the context of specific tumors, such as the clear cell capillary renal cell tumor (CCPRCT), eosinophilic solid and cystic renal cell carcinoma (ESC-RCC), and so-called "other oncocytic tumors", namely the eosinophilic vacuolated tumor (EVT) and low-grade oncocytic tumor (LOT). Their distinctive characteristics and immunophenotypic profiles, along with insights regarding diagnostic challenges and the differential diagnosis of these tumors, are provided. This state-of-the-art review offers valuable insights in biomarkers associated with novel renal tumors, as well as a tool to implement diagnostic strategies in routine practice.
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Affiliation(s)
| | - Roberta Mazzucchelli
- Section of Pathological Anatomy, Department of Biomedical Sciences and Public Health, United Hospitals, Università Politecnica delle Marche, 60126 Ancona, Italy;
| | - Ugo Giovanni Falagario
- Department of Urology and Renal Transplantation, Policlinico Foggia, University of Foggia, 71122 Foggia, Italy (G.C.); (L.C.)
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Angelo Cormio
- Department of Urology, Azienda Ospedaliero-Universitaria Ospedali Riuniti Di Ancona, Università Politecnica Delle Marche, Via Conca 71, 60126 Ancona, Italy
| | - Magda Zanelli
- Pathology Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.Z.); (A.P.)
| | - Andrea Palicelli
- Pathology Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.Z.); (A.P.)
| | - Maurizio Zizzo
- Surgical Oncology Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
| | - Albino Eccher
- Department of Pathology and Diagnostics, University and Hospital Trust of Verona, 37126 Verona, Italy;
| | - Matteo Brunelli
- Department of Pathology and Diagnostics and Public Health, Section of Pathology, University Hospital of Verona, 37126 Verona, Italy;
| | - Andrea Benedetto Galosi
- Department of Urology, Azienda Ospedaliero-Universitaria Ospedali Riuniti Di Ancona, Università Politecnica Delle Marche, Via Conca 71, 60126 Ancona, Italy
| | - Giuseppe Carrieri
- Department of Urology and Renal Transplantation, Policlinico Foggia, University of Foggia, 71122 Foggia, Italy (G.C.); (L.C.)
| | - Luigi Cormio
- Department of Urology and Renal Transplantation, Policlinico Foggia, University of Foggia, 71122 Foggia, Italy (G.C.); (L.C.)
- Department of Urology, Bonomo Teaching Hospital, 76123 Andria, Italy
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Sangoi AR, Nova-Camacho LM, Akgul M, Queipo FJ, Aisa G, Garcia-Martos M, Panizo A. Scars Run Deep: Problematic Morphology and Immunoprofile of Scars in Renal Oncocytomas. Int J Surg Pathol 2024; 32:83-90. [PMID: 37143313 DOI: 10.1177/10668969231171683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In some instances, the central scar of renal oncocytoma can demonstrate entrapped cells with unusual morphology and aberrant immunoprofile creating potential diagnostic confusion. Herein, 100 renal oncocytomas containing scars with embedded epithelial cells were identified from 6 institutions, including nephrectomies (64% partial, 36% radical) of similar laterality (left = 51%) and sex distribution (male = 56%), with patient ages ranging from 38 to 86 years (mean = 64.3years) and tumor sizes ranging from 2 to 16 cm (mean = 5.3 cm). Immunohistochemistry was performed on all tumors for KRT7, KIT, vimentin, and CA9 with staining intensity and extensity separately analyzed. Of 4 architectural patterns of cells within the scar, 60% showed tubular pattern. Of 4 cytologies within the scar, flat/elongated (49%) and cuboidal cells (40%) predominated. Within the scar, 62% showed eosinophilic cytoplasm, with 38% showing both cleared and eosinophilic cytoplasm; notably, 79% showed higher grade nuclei than typical oncocytes. A subset of scar cells showed mucinous-like basophilic secretions (19%). Compared to background renal oncocytoma, tumor cells within the scar were more often positive for vimentin, KRT7, and CA9 and more frequently negativity for KIT. Specifically, of the notable "aberrant" immunoprofiles, 79% showed KRT7 positivity/KIT negativity/vimentin positive, 84% showed vimentin positivity/CA9 positivity, and 78% showed KIT negativity/vimentin positivity/CA9 positivity. While encountering scars within renal oncocytomas is not uncommon, what is not well appreciated is the unique morphology and immunohistochemistry of tumor cells within the scar. Comparing tumor morphology and immunoprofile of the scar to the background oncocytoma is helpful to avoid interpretative confusion.
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Affiliation(s)
- Ankur R Sangoi
- Department of Pathology, Stanford Medical Center, Stanford, CA, USA
| | | | - Mahmut Akgul
- Dpartment of Pathology, Albany Medical Center, Albany, NY, USA
| | - Francisco J Queipo
- Department of Pathology, Hospital Universitario de A Coruna, A Coruna, Spain
| | - Gregorio Aisa
- Department of Pathology, Hospital Universitario de Navarra, Pamplona, Spain
| | - Maria Garcia-Martos
- Department of Pathology, Hospital General Universitario Gregorio Maranon, Madrid, Spain
| | - Angel Panizo
- Department of Pathology, Hospital Universitario de Navarra, Pamplona, Spain
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Wang X, Lovelace E, Pacheco RR, Pacheco R, Schuster ME, Bernstein A, Akgul M, Lightle A. Atrophic Kidney-Like Lesion-Case Report and Review of the Literature. Int J Surg Pathol 2024:10668969241226703. [PMID: 38291647 DOI: 10.1177/10668969241226703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Atrophic kidney-like lesion (AKLL) is a rare kidney lesion, which was recently suggested by the Genitourinary Pathology Society as a provisional entity. As of now, 16 examples of AKLL have been described in the literature. Here we report a new tumor which shows similar clinicopathologic characteristics with those previously reported in AKLL. Immunohistochemical (IHC) studies in the current lesion identified a biphasic staining pattern consisting of a mixture of WT1+/KRT7-/PAX8- large dilated cysts and WT-/KRT7+/PAX8+ small atrophic cysts. Histomorphologic features of AKLL overlap with several neoplastic and non-neoplastic entities which can lead to mischaracterization. Awareness of the differentiating features is likely important when evaluating these lesions.
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Affiliation(s)
- Xin Wang
- Department of Pathology and Laboratory Medicine, Albany Medical Center Hospital, Albany, NY, USA
| | - Elizabeth Lovelace
- Department of Pathology and Laboratory Medicine, Albany Medical Center Hospital, Albany, NY, USA
| | - Richard R Pacheco
- Department of Pathology and Laboratory Medicine, Albany Medical Center Hospital, Albany, NY, USA
| | - Robert Pacheco
- Department of Radiology, Albany Medical Center Hospital, Albany, NY, USA
| | - Michael E Schuster
- Department of Radiology, Albany Medical Center Hospital, Albany, NY, USA
| | - Adrien Bernstein
- Department of Urology, Albany Medical Center Hospital, Albany, NY, USA
| | - Mahmut Akgul
- Department of Pathology and Laboratory Medicine, Albany Medical Center Hospital, Albany, NY, USA
| | - Andrea Lightle
- Department of Pathology and Laboratory Medicine, Albany Medical Center Hospital, Albany, NY, USA
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Li J, Wilkerson ML, Deng FM, Liu H. The Application and Pitfalls of Immunohistochemical Markers in Challenging Diagnosis of Genitourinary Pathology. Arch Pathol Lab Med 2024; 148:13-32. [PMID: 37074862 DOI: 10.5858/arpa.2022-0493-ra] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2023] [Indexed: 04/20/2023]
Abstract
CONTEXT.— The morphologic features of different entities in genitourinary pathology overlap, presenting a diagnostic challenge, especially when diagnostic materials are limited. Immunohistochemical markers are valuable when morphologic features alone are insufficient for definitive diagnosis. The World Health Organization classification of urinary and male genital tumors has been updated for 2022. An updated review of immunohistochemical markers for newly classified genitourinary neoplasms and their differential diagnosis is needed. OBJECTIVE.— To review immunohistochemical markers used in the diagnosis of genitourinary lesions in the kidney, bladder, prostate, and testis. We particularly emphasized difficult differential diagnosis and pitfalls in immunohistochemistry application and interpretation. New markers and new entities in the 2022 World Health Organization classifications of genitourinary tumors are reviewed. Recommended staining panels for commonly encountered difficult differential diagnoses and potential pitfalls are discussed. DATA SOURCES.— Review of current literature and our own experience. CONCLUSIONS.— Immunohistochemistry is a valuable tool in the diagnosis of problematic lesions of the genitourinary tract. However, the immunostains must be carefully interpreted in the context of morphologic findings with a thorough knowledge of pitfalls and limitations.
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Affiliation(s)
- Jianhong Li
- From the Department of Pathology, Geisinger Medical Center, Danville, Pennsylvania (Li, Wilkerson, Liu)
| | - Myra L Wilkerson
- From the Department of Pathology, Geisinger Medical Center, Danville, Pennsylvania (Li, Wilkerson, Liu)
| | - Fang-Ming Deng
- the Department of Pathology, New York University Grossman School of Medicine, New York City (Deng)
| | - Haiyan Liu
- From the Department of Pathology, Geisinger Medical Center, Danville, Pennsylvania (Li, Wilkerson, Liu)
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Yu H, Zhang S, Feng X, Gao F. Multiple myeloma following bone metastasis of renal cell carcinoma: a case report. Front Endocrinol (Lausanne) 2023; 14:1206368. [PMID: 38107521 PMCID: PMC10722259 DOI: 10.3389/fendo.2023.1206368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023] Open
Abstract
Background The clinical manifestations of multiple myeloma (MM) and bone metastatic tumor are both systemic bone pain, which is difficult to distinguish from imaging manifestations, leading to misdiagnosis and missed diagnosis. Case summary We reported a man with a unique case whose tumors were MM with bone metastatic tumor of clear cell renal cell carcinoma (CCRCC). Computed tomography (CT) showed multifocal osteolytic bone destruction, while magnetic resonance imaging (MRI) showed multifocal bone marrow infiltration with soft tissue mass. Pathology and immunohistochemistry established the diagnosis of the coexistence of myeloma with bone metastatic tumor of CCRCC in the spine. Immunotherapy and systemic chemotherapy were adopted in the clinic, and vertebral decompression was performed after anemia was corrected. This case with MM and bone metastatic tumor of CCRCC received radiotherapy and immunotherapy and acquired satisfying outcome after 1 year of follow-up. Conclusion It is difficult to differentiate MM and bone metastatic tumor on imaging, especially when there are bone lesions at the same time, which is an easily missed diagnosis and needs to be comprehensively evaluated in combination with functional procedures, clinical laboratory tests, and histopathology.
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Affiliation(s)
- Hong Yu
- Department of Radiology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Shengnan Zhang
- Department of Radiology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiaohui Feng
- Department of Pathology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Feng Gao
- Department of Pathology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
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Sangoi AR, Al-Obaidy KI, Cheng L, Kao CS, Chan E, Sadasivan S, Levin AM, Alvarado-Cabrero I, Kunju LP, Mehra R, Mannan R, Wang X, Dhillon J, Tretiakova M, Smith SC, Hes O, Williamson SR. Clear cell renal cell carcinoma with focal psammomatous calcifications: a rare occurrence mimicking translocation carcinoma. Histopathology 2023; 82:684-690. [PMID: 36564980 DOI: 10.1111/his.14854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022]
Abstract
AIMS Renal cell carcinoma (RCC) with clear cells and psammoma-like calcifications would often raise suspicion for MITF family translocation RCC. However, we have rarely encountered tumours consistent with clear cell RCC that contain focal psammomatous calcifications. METHODS AND RESULTS We identified clear cell RCCs with psammomatous calcifications from multiple institutions and performed immunohistochemistry and fluorescence and RNA in-situ hybridisation (FISH and RNA ISH). Twenty-one tumours were identified: 12 men, nine women, aged 45-83 years. Tumour size was 2.3-14.0 cm (median = 6.75 cm). Nucleolar grade was 3 (n = 14), 2 (n = 4) or 4 (n = 3). In addition to clear cell pattern, morphology included eosinophilic (n = 12), syncytial giant cell (n = 4), rhabdoid (n = 2), branched glandular (n = 1), early spindle cell (n = 1) and poorly differentiated components (n = 1). Labelling for CA9 was usually 80-100% of the tumour cells (n = 17 of 21), but was sometimes decreased in areas of eosinophilic cells (n = 4). All (19 of 19) were positive for CD10. Most (19 of 20) were positive for AMACR (variable staining = 20-100%). Staining was negative for keratin 7, although four showed rare positive cells (four of 20). Results were negative for cathepsin K (none of 19), melan A (none of 17), HMB45 (none of 17), TFE3 (none of 5), TRIM63 RNA ISH (none of 13), and TFE3 (none of 19) and TFEB rearrangements (none of 12). Seven of 19 (37%) showed chromosome 3p deletion. One (one of 19) showed trisomy 7 and 17 without papillary features. CONCLUSIONS Psammomatous calcifications in RCC with a clear cell pattern suggests a diagnosis of MITF family translocation RCC; however, psammomatous calcifications can rarely be found in true clear cell RCC.
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Affiliation(s)
| | | | - Liang Cheng
- Brown University Warren Albert Medical School, Providence, RI, USA
| | - Chia-Sui Kao
- Stanford Medicine/Stanford University, Stanford, CA, USA
| | - Emily Chan
- University of California, San Francisco, CA, USA
| | | | - Albert M Levin
- Mexican Oncology Hospital SXXI, IMSS, Mexico City, Mexico
| | | | | | | | | | | | - Jasreman Dhillon
- H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | | | | | - Ondrej Hes
- Biopticka Laboratory, Plzen, Czech Republic
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Cipriani NA, Kakkar A. Top 10 Clear Cell Head and Neck Lesions to Contemplate. Head Neck Pathol 2023; 17:33-52. [PMID: 36928734 PMCID: PMC10063749 DOI: 10.1007/s12105-022-01518-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 11/27/2022] [Indexed: 03/18/2023]
Abstract
BACKGROUND Optically clear cytoplasm may occur in neoplastic and non-neoplastic conditions, either as a characteristic feature of a disease entity or as a morphologic rarity, potentially creating diagnostic dilemmas in various organ systems. In the head and neck, clear cell change can occur in lesions of salivary, odontogenic, thyroid, parathyroid, or sinonasal/skull base origin, as well as in metastases to these regions. METHODS This review elaborates the top ten clear cell lesions in the head and neck, emphasizing their distinguishing histologic, immunohistochemical, and molecular attributes, and presents a rational approach to arriving at an accurate classification. RESULTS Cytoplasmic pallor or clearing may be caused by accumulations of glycogen, lipid, mucin, mucopolysaccharides, water, foreign material, hydropic organelles, or immature zymogen granules. Overlapping morphologic features may present a diagnostic challenge to the surgical pathologist. Similarity in immunohistochemical profiles, often due to common cell type, as well as rare non-neoplastic mimics, furthers the diagnostic conundrum. CONCLUSIONS The top ten lesions reviewed in this article are as follows: (1) clear cell carcinoma (salivary and odontogenic), (2) mucoepidermoid carcinoma, (3) myoepithelial and epithelial-myoepithelial carcinoma, (4) oncocytic salivary gland lesions, (5) squamous cell carcinoma, (6) parathyroid water clear cell adenoma, (7) metastatic renal cell carcinoma (especially in comparison to clear cell thyroid neoplasms), (8) sinonasal renal cell-like adenocarcinoma, (9) chordoma, and (10) rhinoscleroma.
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Affiliation(s)
- Nicole A Cipriani
- Department of Pathology, The University of Chicago, 5841 S. Maryland Ave, MC 6101, Chicago, IL, 60637, USA.
| | - Aanchal Kakkar
- All India Institute of Medical Sciences, Department of Pathology, Ansari Nagar, New Delhi, India
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Akgul M, Williamson SR. How New Developments Impact Diagnosis in Existing Renal Neoplasms. Surg Pathol Clin 2022; 15:695-711. [PMID: 36344184 DOI: 10.1016/j.path.2022.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In recent years, several emerging diagnostic entities have been described in renal cell carcinoma (RCC). However, our understanding of well-known and established entities has also grown. Clear cell papillary RCC is now relabeled as a tumor rather than carcinoma in view of its nonaggressive behavior. Renal tumors with a predominantly infiltrative pattern are very important for recognition, as most of these have aggressive behavior, including fumarate hydratase-deficient RCC, SMARCB1-deficient medullary carcinoma, collecting duct carcinoma, urothelial carcinoma, and metastases from other cancers.
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Affiliation(s)
- Mahmut Akgul
- Department of Pathology and Laboratory Medicine, Albany Medical Center, 47 New Scotland Ave, Room F110S, MC81 Albany, NY 12208, USA
| | - Sean R Williamson
- Department of Pathology, Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Mail Code L25 Cleveland, OH 44195, USA.
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Alaghehbandan R, Williamson SR, McKenney JK, Hes O. The Histologic Diversity of Chromophobe Renal Cell Carcinoma With Emphasis on Challenges Encountered in Daily Practice. Adv Anat Pathol 2022; 29:194-207. [PMID: 35470289 DOI: 10.1097/pap.0000000000000349] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chromophobe renal cell carcinoma (ChRCC) is the third most common renal cell carcinoma in adults. The aim of this review is to provide a comprehensive overview highlighting the broad morphologic spectrum of ChRCC, and offer a practical approach for handling cases in daily practice. For the purpose of this review, we classify ChRCC subtypes as (1) classic, (2) eosinophilic, (3) sarcomatoid, and (4) other rare patterns. The concept of eosinophilic ChRCC has significantly evolved, yet it still is one of the major diagnostic challenges pathologists face in routine practice due to its morphologic overlap with renal oncocytoma. Rare patterns of ChRCC have been described over the last few decades, showing a wide histologic spectrum including those with adenomatoid microcystic pigmented, multicystic, neuroendocrine, small cell, and papillary features. ChRCC represents a heterogenous group of neoplasms, demonstrating varied but unique morphologic and genetic profiles. Although the field of ChRCC knowledge is still evolving, rare patterns can present diagnostic challenges if they are not known to pathologists and/or clinicians. Proper and generous tumor sampling along with careful histologic examination allow for recognition of these rare morphologies. The role of routine molecular testing appears to be limited. From a clinical management standpoint, the rare patterns of ChRCC seem to have no definite clinical implications at present and likely can be managed similarly to usual ChRCC. Finally, we will discuss distinctive novel/emerging renal neoplasms previously considered under the spectrum of ChRCC, low-grade oncocytic renal tumor and eosinophilic vacuolated tumor, with regard to their current significance and implications for future classification strategies.
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Affiliation(s)
- Reza Alaghehbandan
- Department of Pathology, Faculty of Medicine, Royal Columbian Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Sean R Williamson
- Robert J. Tomsich Pathology and Laboratory Medicine Institute and Glickman Urological Institute, Cleveland Clinic, Cleveland, OH
| | - Jesse K McKenney
- Robert J. Tomsich Pathology and Laboratory Medicine Institute and Glickman Urological Institute, Cleveland Clinic, Cleveland, OH
| | - Ondrej Hes
- Department of Pathology, Faculty of Medicine and University Hospital in Plzen, Charles University in Prague, Plzen, Czech Republic
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