Succinate Dehydrogenase-deficient Renal Cell Carcinoma Research Articles

Redefining Renal Cell Carcinoma: A Molecular Perspective on Classification and Clinical Implications

Renal cell carcinoma (RCC) is the most common primary tumour of the kidney. RCC is a clinically and pathologically heterogenous entity, which has traditionally been classified under two broad categories: clear-cell and non-clear cell. With improved molecular diagnostic methodologies and genetic testing, the classification of RCC has shifted from a morphological basis to a molecular/genetic focus, and has been systematically updated to reflect these advancements. The new 2022 World Health Organization (WHO) classification of RCC is the most recent of these updates, and contains significant changes, as compared to the previous 2016 classification. The most substantial of these changes is the establishment of a new category of molecularly-defined RCC, including TFE3-rearranged RCC, TFEB-altered RCC, ELOC-mutated RCC, fumarate hydratase-deficient RCC, succinate dehydrogenase-deficient RCC, ALK-rearranged RCC, and SMARCB1-deficient renal medullary carcinoma. In this narrative review, the authors briefly summarise the histopathological characteristics, clinical course, current treatment standards, and future treatment directions of each of these molecularly-defined RCC subtypes.

Succinate dehydrogenase-deficient renal cell carcinoma: A retrospective study, 1999–2018

Background: Succinate dehydrogenase-deficient (SDH-deficient) renal cell carcinoma (RCC) is a rare subtype of RCC. Approximately 0.05% – 0.2% of RCCs are SDH-deficient. It is usually associated with a pathogenic germline variant of the enzyme. Although the tumour is often indolent, it has a strong association with hereditary disease, most commonly paraganglioma and/or pheochromocytoma, and genetic testing is advised. Succinate dehydrogenase-deficient RCC is diagnosed by immunohistochemical (IHC) staining for SDH subunit B (SDHB), with loss of staining confirming SDHB deficiency. The incidence of SDH-deficient RCC in South Africa is unknown.Aim: To determine the incidence of SDH-deficient RCC in the Free State Province and its correlation with the worldwide incidence of 0.05% – 0.2%.Setting: Department of Anatomical Pathology, Universitas Academic Hospital and National Health Laboratory Service (NHLS) in Bloemfontein, South Africa.Methods: A retrospective descriptive study was performed. All primary RCCs diagnosed over a 20-year period (1999–2018) were included. An SDHB IHC stain was performed on all cases. A diagnosis of SDH-deficient RCC required loss of staining in all tumour cells in the presence of internal positive controls.Results: The study included 187 RCC cases. Two cases of SDH-deficient RCC were identified, representing an incidence of 1.1%. Both patients were male and were 22 and 44 years of age, respectively.Conclusion: The incidence of SDH-deficient RCC in central South Africa is slightly higher than global findings.Contribution: This study provides new data on SDH-deficient RCC in the South African context.

Update on Selected Oncocytic Renal Cell Tumors

Renal cell tumors with eosinophilic/oncocytic cells include oncocytic papillary renal neoplasm with reverse polarity, oncocytoma, chromophobe renal cell carcinoma, hybrid oncocytic/chromophobe renal tumor, succinate dehydrogenase-deficient renal cell carcinoma, translocation-associated renal cell carcinoma, etc. Recently, several novel and evolving oncocytic renal tumors have been identified, such as eosinophilic solid and cystic renal cell carcinoma, eosinophilic vacuolated tumor, and low-grade oncocytic tumor. In addition, fumarate hydratase-deficient renal cell carcinoma occasionally presents with a low-grade oncocytic morphology. Although these entities demonstrate some overlapping morphological features with oncocytoma and chromophobe renal cell carcinoma, they do have some unique morphological, immunohistochemical, and molecular profiles. In this review, we present an update on selected oncocytic renal cell tumors (eosinophilic vacuolated tumor, low-grade oncocytic tumor, eosinophilic solid and cystic renal cell carcinoma, low-grade fumarate hydratase-deficient renal cell carcinoma, and hybrid oncocytic/chromophobe renal tumor) and discuss their morphologies, immunohistochemical profiles, molecular genetic profiles, and biological behaviors.

Tumorigenesis Mechanisms Found in Hereditary Renal Cell Carcinoma: A Review.

Renal cell carcinoma is a heterogenous cancer composed of an increasing number of unique subtypes each with their own cellular and tumor behavior. The study of hereditary renal cell carcinoma, which composes just 5% of all types of tumor cases, has allowed for the elucidation of subtype-specific tumorigenesis mechanisms that can also be applied to their sporadic counterparts. This review will focus on the major forms of hereditary renal cell carcinoma and the genetic alterations contributing to their tumorigenesis, including von Hippel Lindau syndrome, Hereditary Papillary Renal Cell Carcinoma, Succinate Dehydrogenase-Deficient Renal Cell Carcinoma, Hereditary Leiomyomatosis and Renal Cell Carcinoma, BRCA Associated Protein 1 Tumor Predisposition Syndrome, Tuberous Sclerosis, Birt-Hogg-Dubé Syndrome and Translocation RCC. The mechanisms for tumorigenesis described in this review are beginning to be exploited via the utilization of novel targets to treat renal cell carcinoma in a subtype-specific fashion.

Expanding the clinicopathological spectrum of succinate dehydrogenase-deficient renal cell carcinoma with a focus on variant morphologies: a study of 62 new tumors in 59 patients

AbstractMost succinate dehydrogenase (SDH)-deficient renal cell carcinomas (RCCs) demonstrate stereotypical morphology characterized by bland eosinophilic cells with frequent intracytoplasmic inclusions. However, variant morphologic features have been increasingly recognized. We therefore sought to investigate the incidence and characteristics of SDH-deficient RCC with variant morphologies. We studied a multi-institutional cohort of 62 new SDH-deficient RCCs from 59 patients. The median age at presentation was 39 years (range 19–80), with a slight male predominance (M:F = 1.6:1). A relevant family history was reported in 9 patients (15%). Multifocal or bilateral tumors were identified radiologically in 5 patients (8%). Typical morphology was present at least focally in 59 tumors (95%). Variant morphologies were seen in 13 (21%) and included high-grade nuclear features and various combinations of papillary, solid, and tubular architecture. Necrosis was present in 13 tumors, 7 of which showed variant morphology. All 62 tumors demonstrated loss of SDHB expression by immunohistochemistry. None showed loss of SDHA expression. Germline SDH mutations were reported in all 18 patients for whom the results of testing were known. Among patients for whom follow-up data was available, metastatic disease was reported in 9 cases, 8 of whom had necrosis and/or variant morphology in their primary tumor. Three patients died of disease. In conclusion, variant morphologies and high-grade nuclear features occur in a subset of SDH-deficient RCCs and are associated with more aggressive behavior. We therefore recommend grading all SDH-deficient RCCs and emphasize the need for a low threshold for performing SDHB immunohistochemistry in any difficult to classify renal tumor, particularly if occurring at a younger age.

Succinate dehydrogenase-deficient renal cell carcinoma:a clinicopathological, ultrastructural and molecular analysis

Objective: To investigate the clinicopathological features, immunophenotype, ultrastructure, genetic alterations and prognosis of succinate dehydrogenase-deficient renal cell carcinoma (SDH RCC). Methods: A total of 11 SDH RCCs, diagnosed from 2010 to 2019, were selected from the Department of Pathology of Nanjing Jingling Hospital, Nanjing University School of Medicine for clinicopathologic, immunohistochemical (IHC), ultrastructural investigation and follow-up. The molecular features of seven cases were analyzed by the panel-targeted DNA next generation sequencing (NGS). Results: There were seven males and four females, with ages ranging from 24 to 62 years (mean 41.4 years, median 41 years). Microscopically, SDH RCC was mainly composed of solid and tubular structures with local cystic change. Four cases showed nested or trabecular structure distributed in a loose hypocellular connective tissue or around scar, similar to oncocytoma. The neoplastic cells demonstrated flocculent eosinophilic cytoplasm with typical intracytoplasmic vacuoles. Immunohistochemically, eight cases were negative for SDHB; three cases showed focal and weak expression, whereas normal renal tubular and vascular endothelial cells demonstrated strong cytoplasmic staining. NGS of DNA targeted-panel detected pathogenic mutations of SDHB gene in seven cases (including three cases with equivocal IHC expression of SDHB), without any mutations in other SDH related genes. There were four cases of SDHB missense mutation, one case of frameshift mutation, one case of splicing mutation, and one case of acquired stop codon mutation. Conclusions: SDH RCC is a distinct variant of RCCs with genetic tendency or with hereditary cancer syndrome. NGS is recommended to detect the related gene mutations for a definitive diagnosis. The patients should be closely followed up.

Immunohistochemistry for the diagnosis of renal epithelial neoplasms.

Despite the increasing number of newly identified renal neoplasms, the diagnosis of renal cell carcinoma (RCC) can usually be reached with careful histologic examination and a limited immunohistochemical (IHC) panel. Clear cell, papillary, chromophobe RCC and oncocytoma account for more than 90% of renal neoplasia in adults, and sophisticated ancillary tools are usually unnecessary. Renal tumors with entity-defining genetic alterations may ultimately require molecular confirmation via cytogenetics or sequencing technologies, such as RCC with TFE3, TFEB, or ALK gene rearrangements, or TFEB amplified RCC. In fumarate hydratase-deficient and succinate dehydrogenase-deficient RCC, highly specific IHC markers can strongly suggest the diagnosis. In the metastatic setting, PAX8 and carbonic anhydrase 9 are among the most helpful markers for confirming RCC and clear cell type, respectively; however, caution should be exercised in the absence of a current or historical renal mass. In diagnostically challenging cases, such as renal eosinophilic tumors with low-grade nuclear features, or infiltrative high-grade tumors, careful examination coupled with a judicious panel of IHC markers usually resolves the diagnosis. This review offers concise algorithms for diagnosis of kidney neoplasia with the latest recognized, provisional, and emerging entities to daily pathology practice.

Prostate cancer nomenclature at diagnosis can affect treatment decisions.

Prostate cancer nomenclature at diagnosis can affect treatment decisions.

ПОЧЕЧНО-КЛЕТОЧНАЯ КАРЦИНОМА С ДЕФИЦИТОМ СУКЦИНАТДЕГИДРОГЕНАЗЫ В У РЕБЕНКА 15 ЛЕТ С СИНДРОМОМ НАСЛЕДСТВЕННОЙ ФЕОХРОМОЦИТОМЫ И ПАРАГАНГЛИОМЫ 4-го ТИПА

Succinate dehydrogenase-deficient renal cell carcinoma (SDH-deficient RCC) is histological variant of RCC recently recognized and included in the classification of renal tumors. SDH-deficient RCC constitutes only 0,02–0,5% of all RCC. The main role in the development of this malignant neoplasm (MN) belongs to mutations in the genes of succinate dehydrogenase (SDHx). The article presents a clinical case report of SDH-deficient RCC in the 15-year-old child. RCC developed as a consequence of the syndrome of hereditary pheochromocytoma and paraganglioma type 4. A literature review describes the histological and molecular genetic characteristics of SDH-deficient RCC, the clinical picture, approaches to therapy and monitoring of patients, as well as indications for genetic testing of patients and their relatives to identify cancer predisposition syndromes.

Renal oncocytoma with prominent xanthomatous reaction. A rare histopathological variant of oncocytoma.

Renal oncocytoma (RO) is a distinctive neoplasm with a well-recognized gross and cytoarchitectural appearance. However, on some occasions, it may show uncommon, atypical, or worrisome gross and microscopic features potentially generating diagnostic difficulties. We herein review the oncocytoma variant characterized by a significant intraneoplastic xanthomatous reaction that produces a variegated macroscopic appearance. This feature may pose a genuine diagnostic problem with conventional (clear cell) renal cell carcinoma (RCC) because this reaction creates a departure from the typical uniform, tan-brown appearance of oncocytoma. The microscopic presence of foamy macrophages in RO may potentially lead to diagnostic difficulties with tumors exhibiting eosinophilic cells and significant infiltration for lipid-laden foamy macrophages such as cystic RCC, unclassified RCC rich in foamy macrophages, the solid variant of papillary RCC with oncocytic features, post-neuroblastoma RCC, succinate dehydrogenase-deficient RCC, mucinous-poor tubular and spindle cell carcinoma, and the oncocytic variant of the epithelioid angiomyolipoma. In conflictive cases, an immunohistochemical panel should help to solve the diagnostic problem. Therefore, the presence of abundant foamy macrophages should not dissuade the pathologist from establishing a diagnosis of RO. Prominent xanthomatous reaction despite its low frequency (4.3%) can be considered an additional feature of RO. Thus, RO should be added to the list of renal tumors that can show a significant reaction of lipid-laden foamy macrophages. Besides, Gamna–Gandy bodies can be present in this tumor.

Contemporary Characterization and Recategorization of Adult Unclassified Renal Cell Carcinoma.

Our recent study of early-onset unclassified eosinophilic renal cell carcinoma (RCC) demonstrated that two third of cases could be reclassified by performing a limited number of immunohistochemistry stains. Following the same approach, we aimed to investigate what proportion of adult unclassified RCC could be reclassified. We identified 79 cases. The mean age at presentation was 58 years (range, 29 to 84 y). Tumors were grouped based on their predominant morphologic features as oncocytic (n=23); papillary (n=22); clear cell (n=22); mucinous tubular and spindle cell (MTSC; n=5); rhabdoid (n=4); or lacking a dominant pattern (n=3). By reviewing the morphologic features and performing ancillary studies, we were able to reclassify 10 cases (13%). Four cases were positive for CK20 and showed morphologic features consistent with eosinophilic solid and cystic RCC. Four cases were reclassified as MTSC based on VSTM2A expression by RNA in situ hybridization. One case was negative for SDHB and reclassified as succinate dehydrogenase-deficient RCC. None of the cases showed loss of expression of fumarate hydratase. One case was diffusely positive for CK7 and negative for CD117 and reclassified as a low-grade oncocytic tumor. Four cases were positive for both cathepsin-K and TFE3 by immunohistochemistry, although fluorescence in situ hybridization failed to identify rearrangement in either TFE3 or TFEB genes. Of the tumors that remained unclassified, those with oncocytic features were less likely to be a high grade (odds ratio [OR]=0.22, P=0.013) or advanced stage (OR=0.19, P=0.039) and were more common in women (OR=3.4, P=0.05) compared with those without oncocytic features. Tumors with rhabdoid morphology were associated with advanced stage (relative risk=3.6, P=0.009), while tumors with clear cell or papillary features had a wide range of grades and stages at presentation. In summary, the most frequent reclassified entity is eosinophilic solid and cystic RCC. Investigation of expression of succinate dehydrogenase or fumarate hydratase in individuals older than 35 years with unclassifiable tumors is low yield in the absence of specific morphologic features. A subset of MTSC without well-developed morphologic features can be reclassified by using RNA-ISH for VSTM2A. Recognition of more-recently described RCC subtypes allows for their distinction from the unclassified subtype and improves the prognostic information provided.

Les cancers du rein héréditaires vus par le pathologiste en 2020

Hereditary predispositions to adult kidney tumors involve around 5% of tumors and include a dozen of autosomal dominant syndromes. The most frequent tumors encountered in these setting are clear cell renal cell carcinomas, papillary renal cell carcinomas, chromophobe renal cell carcinomas and angiomyolipomas. Their detection is essential in order to adapt individual care and perform genetic screening of at-risk relatives, especially in the national french network PREDIR, labeled by the National Cancer Institute and dedicated to hereditary predispositions to kidney tumors. Targeted genetic analysis, which was guided in particular by the renal tumor subtype, has recently evolved into genetic analysis using panels of genes. Pathologist contribution's remains however central in the diagnosis of hereditary forms since we currently have immunohistochemical biomarkers that allow us to diagnose two specifically hereditary entities: hereditary leiomyomatosis and renal cell carcinoma associated-renal cell carcinoma, associated with a loss of fumarate hydratase and succinate dehydrogenase-deficient renal cell carcinoma associated with a loss of succinate deshydrogenase B expression. These diagnoses must however be confirmed by the identification of pathogenic germline variation in the corresponding genes. Improvement of kidney tumors characterization has also lead to identify new subtypes, expanding the algorithm of renal tumors associated with hereditary setting. Here we aim to review all subtypes of adult renal tumors encountered in predisposition syndromes.

Clinicopathological features of succinate dehydrogenase-deficient renal cell carcinoma

目的： 探讨琥珀酸脱氢酶缺陷型肾细胞癌（SDH-RCC）的临床病理特征、免疫表型及基因突变。 方法： 收集江苏省苏北人民医院和靖江市人民医院SDH-RCC病例各1例，对其临床资料、病理形态、免疫标记及基因检测结果进行分析，同时复习文献。 结果： 肉眼观察肿块切面灰白或棕色，有边界较清楚的假纤维包膜分隔，瘤细胞呈巢状、小管状排列，细胞质丰富，嗜酸性或较空淡，细胞质内含特征性的包涵物或小液泡，包涵物内见伊红染丝状物。瘤组织内特别是瘤组织边缘见卷入正常的肾小管。免疫组织化学标记为SDHA阳性、SDHB阴性；基因检测结果例1肿瘤组织显示SDHB第3号外显子NM_OO30002：C.268C>T R[CGA]>*[TGA]；NP_002991.2：p.Arg90Ter R（Arg）>*（Ter）。例2肿瘤组织显示SDHB第8号外显子NM_OO30002：C.785_786insG；NP_002991.2：p.I1e263fs。 结论： SDH-RCC是一种特殊类型的肾细胞癌，正确诊断对临床医师的精准治疗、预测患者预后具有提示意义。.

Succinate Dehydrogenase–Deficient Renal Cell Carcinoma With Sarcomatoid Features

Abstract Succinate dehydrogenase (SDH) complex deficiency syndrome is an autosomal dominant syndrome with mutations in the SDH gene characterized by multiple tumor types, including paragangliomas, pheochromocytomas, gastrointestinal stromal tumors, thyroid tumors, testicular seminoma, neuroblastomas, and, less commonly, renal cell carcinoma. SDH-deficient renal cell carcinoma is a distinct and rare subtype of renal cell carcinoma, typically with a good prognosis, that demonstrates histologic features including cytoplasmic inclusions and vacuoles with a loss of SDH subunit B immunostaining. We present a case of succinate dehydrogenase–deficient renal cell carcinoma with sarcomatoid features in a 24-year-old male who initially presented with hematuria and flank pain. An MRI of the abdomen showed a large enhancing mass in the upper pole of the kidney. He underwent a radical nephrectomy and was found to have an 11.0 × 10.5 × 10.2-cm variegated and lobular mass in the upper pole of the kidney. Microscopic examination showed sheets of cells with cleared out cytoplasm, cytoplasmic inclusions, and vacuoles. Areas of the mass showed sarcomatoid features and necrosis. The mass extended into the pelvicalyceal system and metastasized to the adrenal gland. An SDH B immunostain was performed on the specimen and was negative, confirming the diagnosis of SDH-deficient renal cell carcinoma. Subsequently, the patient underwent genetic testing and was found to have an SDHB germline mutation.

New and emerging renal entities: a perspective post-WHO 2016 classification.

Renal tumours include a heterogeneous and diverse spectrum of neoplasms. Recent advances in this field have significantly improved our understanding of the morphological, immunohistochemical, molecular, epidemiological and clinical characteristics of renal tumours, which led to the new Vancouver classification of renal neoplasia and the new World Health Organization (WHO) classification of renal cell tumours. This review aims to summarise the new information and evidence on several new and emerging/provisional renal entities, which were mostly generated after the recent classification of renal neoplasia. We include in this review the following new and emerging/provisional renal entities: succinate dehydrogenase-deficient renal cell carcinoma, thyroid-like follicular carcinoma of the kidney, anaplastic lymphoma kinase rearrangement-associated renal cell carcinoma, renal cell carcinomas with prominent smooth muscle stroma, fumarate hydratase-deficient renal cell carcinoma, biphasic squamoid papillary renal cell carcinoma, eosinophilic solid and cystic renal cell carcinoma, atrophic kidney-like renal cell carcinoma, clear cell renal cell carcinoma with giant cells and emperipolesis, Warthin-like papillary renal cell carcinoma, and low-grade oncocytic renal tumour (CD117-negative; cytokeratin 7-positive). Some of these entities, such as succinate dehydrogenase-deficient renal cell carcinoma, have already been recognised as new entities in the WHO classification, and some have been recognised as provisional/emerging entities. However, we include in this review several additional entities that, on the basis of the published evidence, also warrant this designation. We hope that this review will ease the navigation through this complex and evolving field, and will inform and stimulate new studies and discussions.

Clear Cell Renal Cell Carcinoma

Renal cell carcinoma, clear cell type, forming a mass in the lower and mid portion of the kidney. Which is the most common subtype of renal cell carcinoma?a.Clear cellb.Papillaryc.Chromophobed.Unclassified Answer: a. Clear cell Clear cell renal cell carcinoma is the most common subtype of renal cell carcinoma (RCC), comprising 65% to 70% of RCC.1Moch H. Humphrey P.A. Ulbright T.M. Reuter V.E. WHO Classification of Tumours of the Urinary System and Male Genital Organs.4th ed. IARC Press, Lyon, France2016Google Scholar Papillary RCC comprises 15% to 20% and chromophobe RCC comprises 5% to 7% of RCC.1Moch H. Humphrey P.A. Ulbright T.M. Reuter V.E. WHO Classification of Tumours of the Urinary System and Male Genital Organs.4th ed. IARC Press, Lyon, France2016Google Scholar Other renal cell tumor subtypes include collecting duct carcinoma, renal medullary carcinoma, mucinous tubular and spindle cell carcinoma, RCC unclassified, papillary adenoma, and oncocytoma. Recently described renal cell tumors include multilocular cystic renal neoplasm of low malignant potential, MiT family translocation RCC, tubulocystic RCC, acquired cystic disease–associated RCC, clear cell papillary RCC, succinate dehydrogenase–deficient RCC, and hereditary leiomyomatosis and RCC-associated RCC. Additional emerging/provisional entities include oncocytic RCC occurring after neuroblastoma, thyroid-like follicular RCC, ALK rearrangement–associated RCC, and RCC with (angio)leiomyomatous stroma.1Moch H. Humphrey P.A. Ulbright T.M. Reuter V.E. WHO Classification of Tumours of the Urinary System and Male Genital Organs.4th ed. IARC Press, Lyon, France2016Google Scholar Although complex, the classification of renal cell tumors is important diagnostically and prognostically.

Uncovering Hereditary Tumor Syndromes: Emerging Role of Surgical Pathology.

With the increased use of modern next generation sequencing technologies in routine molecular pathology practice, the proportion of cancer cases with a definite or probable hereditary background seems to be steadily increasing. Currently, it is assumed that ≥10% of all malignancies develop in the setting of germline predisposition. Diagnosis and recognition of cancer predisposition syndromes relies not rarely on distinctive histopathological features that proved to be highly valuable and reproducible in uncovering those diseases that would otherwise have gone undetected by clinicians as being hereditary in nature. This is especially true in case of new mutations without suspicious family history. Example of such entities are fumarate hydratase-deficient renal cell carcinoma (RCC), succinate dehydrogenase-deficient RCC, hereditary gastrointestinal stromal tumor syndromes and many other diseases. It is remarkable that many of these inherited cancer syndromes do present as unifocal disease with highly variable age of onset so that many of them are misinterpreted as sporadic on clinical grounds. Availability of specialized cancer screening programs and disease-specific follow-up schemes for several hereditary cancer syndromes encourages the recognition of such disorders, so that "at risk patients" can be enrolled in such programs for early detection and timely intervention/ treatment of these malignancies which are in the majority of cases aggressive. In several conditions, as in familial adenomatous polyposis coli (FAP), well established prophylactic surgical interventions may be adopted to prevent the disease manifestations, highlighting the importance of the timely recognition of these potentially life-limiting neoplasms. In this review, the clinicopathological, demographic and histological features that are considered highly suggestive of a hereditary basis of "a neoplasm under consideration" are highlighted and discussed briefly. The details of some of these entities are in addition dealt with in reviews devoted to them in this special issue.

Modern Pathologic Diagnosis of Renal Oncocytoma.

Oncocytoma is a well-defined benign renal tumor, with classic gross and histologic features, including a tan or mahogany-colored mass with central scar, microscopic nested architecture, bland cytology, and round, regular nuclei with prominent central nucleoli. As a result of variations in this classic appearance, difficulty in standardizing diagnostic criteria, and entities that mimic oncocytoma, such as eosinophilic variant chromophobe renal cell carcinoma and succinate dehydrogenase-deficient renal cell carcinoma, pathologic diagnosis remains a challenge. This review addresses the current state of pathologic diagnosis of oncocytoma, with emphasis on modern diagnostic markers, areas of controversy, and emerging techniques for less invasive diagnosis, including renal mass biopsy and advanced imaging.

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

Abstract Context and Objectives The 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 synthesis Several 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 summary There 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.

What is new in Genitourinary Pathology? Recent developments and highlights of the new 2016 World Health Organization classification of tumors of the urinary system and male genital organs

The recently published 2016 World Health Organization (WHO) Classification of Tumors of the Urinary System and Male Genital Organs stems from the accumulated knowledge and data collected during the last 12 years, since the previous edition of the WHO “blue book” 2004. The major changes in prostate pathology include the introduction of a novel grading system for prostate cancer (Grade Groups/International Society of Urological Pathology (ISUP) grades 1–5), the recognition of intraductal carcinoma as a new entity, and the terminological changes regarding the neuroendocrine prostatic neoplasms. In bladder and urothelial tract, within the spectrum of flat and non-invasive lesions, a newly introduced term “urothelial proliferation of uncertain malignant potential” replaced the term “urothelial hyperplasia”, and the term “urothelial dysplasia” was better defined. A category of “invasive urothelial carcinoma with divergent differentiation” was introduced for tumors showing a component of “usual type” urothelial carcinoma combined with other morphologies. A new WHO/ISUP renal tumor grading system was recommended (Grade 1–4). The definition of renal papillary adenoma was modified and expanded to include papillary neoplasms measuring up to 1.5 cm. Several new epithelial renal tumors were recognized as new entities including: hereditary leiomyomatosis and renal cell carcinoma (RCC) syndrome–associated RCC, succinate dehydrogenase–deficient RCC, tubulocystic RCC, acquired cystic disease–associated RCC, and clear cell papillary RCC. In testis pathology, intratubular proliferations of testicular germ cell tumors were renamed as “germ cell neoplasia in-situ” (GCNIS), and the testicular neoplasms were divided into two main groups: derived from or unrelated to GCNIS. A major change in penile pathology was the introduction of a new classification of penile squamous cell carcinoma, based on the presence of human papillomavirus (HPV), which characterizes penile tumor subtypes as HPV-related or non-HPV-related. A similar distinction was introduced for the preneoplastic penile intraepithelial precursor lesion (PeIN) into non-HPV related (differentiated PeIN) and HPV-related types (undifferentiated PeIN). In this review, we provide a summary and highlight the changes in the genitourinary pathology introduced by the 2016 WHO blue book, and we also discuss some recent developments that may impact the practice of genitourinary pathology in the near future.