Kidney Tumors: New and Emerging Kidney Tumor Entities.

This review summarizes current knowledge on several novel and emerging renal entities, including eosinophilic solid and cystic renal cell carcinoma (RCC), RCC with fibromyomatous stroma, anaplastic lymphoma kinase-rearranged RCC, low-grade oncocytic renal tumor, eosinophilic vacuolated tumor, thyroidlike follicular RCC, and biphasic hyalinizing psammomatous RCC. Their clinical features, gross and microscopic morphology, immunohistochemistry, and molecular and genetic features are described. The diagnosis of most of them rests on recognizing their morphologic features using immunohistochemistry. Accurate diagnosis of these entitles will further reduce the category of "unclassifiable renal carcinomas/tumors" and will lead to better clinical management and improved patient prognostication.

Should grade group 1 prostate cancer be reclassified as "non-cancer"? A pathology community perspective.

Overdiagnosis and overtreatment of Grade Group 1 (GG 1) prostate cancer remains a significant health care problem despite of its improved risk assessment and uptake in conservative management. Removing the cancer label from these non-lethal cancers has been proposed as an expedient way to reduce potential physical, psychological and financial harm to patients. Such a nomenclatural change necessitates a multidisciplinary team effort by clinicians and pathologists. Genitourinary Pathology Society recently conducted a survey of its members, gauging their awareness of this controversy and their position on whether GG 1 prostate cancer should be reclassified. Most respondents (196, 81.7%) opposed removing the cancer label from GG 1 cancer, 33 (13.8%) supported a change in nomenclature, while 11 (4.6%) responded that they were uncertain. Of those who supported the reclassification, 17 (51.5%) supported the change for radical prostatectomy only, 4 (12.1%) for biopsy only, and 12 (36.4%) for both biopsy and radical prostatectomy. This survey results highlight the gap between pathologists and clinicians in whether GG 1 prostate cancer should be labeled as "non-cancer," and calls for continued debates and conversations between pathologists and clinicians, and further studies on the biology, diagnostic reproducibility, and ideal management of GG 1 prostate cancer in order to make a more evidence-based decision for patients.

Kidney Tumors: New and Emerging Kidney Tumor Entities.

This review summarizes current knowledge on several novel and emerging renal entities, including eosinophilic solid and cystic renal cell carcinoma (RCC), RCC with fibromyomatous stroma, anaplastic lymphoma kinase-rearranged RCC, low-grade oncocytic renal tumor, eosinophilic vacuolated tumor, thyroidlike follicular RCC, and biphasic hyalinizing psammomatous RCC. Their clinical features, gross and microscopic morphology, immunohistochemistry, and molecular and genetic features are described. The diagnosis of most of them rests on recognizing their morphologic features using immunohistochemistry. Accurate diagnosis of these entitles will further reduce the category of "unclassifiable renal carcinomas/tumors" and will lead to better clinical management and improved patient prognostication.

Extrarenal renal cell carcinoma arising in the kidney proximity but without an identifiable renal primary - an intriguing dilemma: report of three cases and review of the literature.

AIM: To raise awareness of the existence of extrarenal renal cell carcinoma (RCC). METHODS AND RESULTS: We report three patients with extrarenal RCC found in the renal proximity, but unattached to the kidney. None had a history of RCC or an identifiable primary renal neoplasm at the time of the diagnosis and on follow-up. The patients included two males and one female aged 57, 77, and 63 years, respectively. One carcinoma was found in the perirenal tissue adjacent to the adrenal, one involved the adrenal gland, and one was a retroperitoneal mass found within the lymph nodes. Two extrarenal RCCs represented clear-cell RCCs and one was an unclassifiable RCC. No patient had evidence of metastases at presentation and disease progression during the follow-up. This report adds to the literature on this unusual clinical scenario and further supports the concept of extrarenal RCC, which is not a well-recognized clinical phenomenon. We also reviewed other similar reports documenting the absence of identifiable renal primaries in the setting of either disseminated metastatic disease or isolated distant metastases of presumed renal origin. Similarly, some carcinomas of apparent renal derivation have been also identified during a work-up of metastatic carcinomas of unknown primary. CONCLUSIONS: There should be an awareness of this unusual and intriguing clinical scenario that currently lacks a definitive explanation and standardized therapy strategies. Establishing a correct diagnosis may allow treatment with specific targeted therapies in selected clinical cases.

p53 null phenotype is a "positive result" in urothelial carcinoma in situ.

The concept of a "p53 null phenotype" (complete loss of staining) is well-recognized in the gynecologic pathology literature, implicitly reflecting that this staining pattern represents a TP53 mutation. However, in the genitourinary pathology literature, a p53 null phenotype has only been addressed regarding the prognosis of invasive urothelial carcinoma, and not as a diagnostic biomarker for urothelial carcinoma in situ (CIS). Herein, 25 cases of urothelial carcinoma in situ [diagnoses made on hematoxylin and eosin (H&E) stained sections] showing null pattern p53 staining were retrieved from 22 different patients (16 males and 6 females, age range 52-85 years; average 69.6 years), most commonly showing large cell pleomorphic pattern morphology. One representative tissue block per case was selected for next-generation DNA sequencing (NGS). All 21 cases (100%) passing quality control for NGS showed at least 1 TP53 mutation (majority nonsense or frameshift mutations), including 3 cases with 2 mutations and 3 cases with 3 mutations. Three patients with multiple available samples harbored 1 or more shared TP53 mutations at 2 different time points, indicating clonality of the temporally distinct lesions. Additionally, 2 patients had an additional unique TP53 mutation at a later time point, suggesting intratumoral heterogeneity and/or temporal clonal evolution. While urothelial CIS remains an H&E diagnosis in most cases, a p53 immunostain may be useful in a subset of challenging cases. This study demonstrates that a p53 null phenotype represents an aberrant result in urothelial CIS with supportive molecular analysis showing a previously unknown level of complexity for TP53 mutations among these noninvasive lesions. Adequate recognition of the p53 null phenotype as a "biologically supportive result", similar to strong and diffuse staining with p53, is important and may warrant a formal consensus statement for recommended p53 reporting (i.e., "wild type" versus "aberrant or mutant").

Granulomas associated with renal neoplasms: A multi-institutional clinicopathological study of 111 cases.

AIMS: Formal depiction of granulomatous inflammation associated with renal neoplasms has mainly consisted of case reports. Herein, we investigate the clinicopathological features and potential significance of granulomas associated with renal tumours from a large multi-institutional cohort. METHODS AND RESULTS: One hundred and eleven study cases were collected from 22 institutions, including 57 partial nephrectomies and 54 radical nephrectomies. Patient ages ranged from 27 to 85 years (average = 60.1 years; male = 61%). Renal neoplasms included clear cell renal cell carcinoma (RCC; 86%), papillary RCC (8%), chromophobe RCC (3%), clear cell papillary RCC (1%), mixed epithelial stromal tumour (1%) and oncocytoma (1%). Granulomas were peritumoral in 36%, intratumoral in 24% and both in 40% of cases. Total granuloma count per case ranged from one to 300 (median = 15) with sizes ranging from 0.15 to 15 mm (mean = 1.9 mm). Necrotising granulomas were seen in 14% of cases. Histochemical stains for organisms were performed on 45% of cases (all negative). Sixteen cases (14%) had a prior biopsy/procedure performed, and eight patients had neoadjuvant immunotherapy or chemotherapy. Eleven patients (10%) had a confirmed diagnosis of sarcoidosis, including five in whom sarcoidosis was diagnosed after nephrectomy. CONCLUSION: Based on this largest case-series to date, peri-/intratumoral granulomas associated with renal neoplasms may be more common than initially perceived. The extent of granulomatous inflammation can vary widely and may or may not have necrosis with possible aetiologies, including prior procedure or immunotherapy/chemotherapy. Although a clinical association with sarcoidosis is infrequent it can still occur, and the presence of granulomas warrants mention in pathology reports.

Low-grade oncocytic tumor (LOT) - a new renal entity ready for a prime time: An updated review.

Low-grade oncocytic tumor (LOT) of kidney has been recently proposed as a new renal entity. LOT was identified in the spectrum of oncocytic renal tumors with overlapping features between oncocytoma and eosinophilic chromophobe renal cell carcinoma, or it has been labelled as one of those entities in prior studies and in practice. LOT is often a single, relatively small tumor, found in a non-syndromic setting, but rare examples of multiple LOTs or admixed with other tumors have been found in patients with tuberous sclerosis complex. LOT typically has solid architecture, and it is composed of eosinophilic cells, with round to oval 'low-grade' nuclei, lacking irregularities and showing focal perinuclear halos. Sharp transition into edematous stromal areas, with scattered or loosely arranged cells are frequently found. LOT has a consistent immunohistochemical profile with diffuse reactivity for cytokeratin 7 and absent (or rarely weak) expression for CD117, a profile different from oncocytoma and eosinophilic chromophobe renal cell carcinoma. Similarly, in contrast to those entities, it also lacks or shows only weak expression for FOXI1. Recent studies have shown that LOT has a molecular/genetic profile different from other renal tumors, with frequent alterations affecting the MTOR/TSC pathway genes. LOT demonstrates either disomic pattern or deletions of 19p13, 19q13 and 1p36, and lacks complete chromosomal losses or gains. In all published studies to date, LOT has shown benign behavior. In this review, we summarize the evidence from recently published studies, which strongly supports the conclusion that LOT is a distinct and unique renal entity.

Eosinophilic vacuolated tumor (EVT) of kidney demonstrates sporadic TSC/MTOR mutations: next-generation sequencing multi-institutional study of 19 cases.

A distinct renal tumor has recently been described as "high-grade oncocytic renal tumor" and "sporadic renal cell carcinoma with eosinophilic and vacuolated cytoplasm". The Genitourinary Pathology Society (GUPS) consensus proposed a unifying name "eosinophilic vacuolated tumor" (EVT) for this emerging entity. In this multi-institutional study, we evaluated 19 EVTs, particularly their molecular features and mutation profile, using next-generation sequencing. All cases were sporadic and none of the patients had a tuberous sclerosis complex. There were 8 men and 11 women, with a mean age of 47 years (median 50; range 15-72 years). Average tumor size was 4.3 cm (median 3.8 cm; range 1.5-11.5 cm). All patients with available follow-up data (18/19) were alive and without evidence of disease recurrence or progression during the follow-up, ranging from 12 to 198 months (mean 56.3, median 41.5 months). The tumors were well circumscribed, but lacked a well-formed capsule, had nested to solid growth, focal tubular architecture, and showed ubiquitous, large intracytoplasmic vacuoles, round to oval nuclei, and prominent nucleoli. Immunohistochemically, cathepsin K, CD117, CD10, and antimitochondrial antigen were expressed in all cases. Other positive stains included: PAX8, AE1/AE3 and CK18. CK7 was typically restricted only to rare scattered cells. Vimentin, HMB45, melan-A, and TFE3 were negative in all cases. All tumors showed retained SDHB. All cases (19/19) showed non-overlapping mutations of the mTOR pathway genes: TSC1 (4), TSC2 (7), and MTOR (8); one case with MTOR mutation showed a coexistent RICTOR missense mutation. Low mutational rates were found in all samples (ranged from 0 to 6 mutations/Mbp). Microsatellite instability and copy number variations were not found in any of the 17 analyzable cases. EVT represents an emerging renal entity that shows a characteristic and readily identifiable morphology, consistent immunohistochemical profile, indolent behavior, and mutations in either TSC1, TSC2, or MTOR genes.

What's new in the WHO 2022 classification of kidney tumours?

The World Health Organization (WHO) 2022 classification of urinary and male genital tumours (5th edition) has significantly improved our understanding of the morphologic, immunohistochemical, and molecular characteristics of renal tumours. The aim of this review is to outline the most important changes and diagnostic updates in the WHO 2022 classification of kidney tumours. A major change in this edition is the grouping of renal tumours into broader categories that include "clear cell renal tumours", "papillary renal tumours", "oncocytic and chromophobe renal tumours", "collecting duct tumours" as well as adding two categories of "other renal tumours" and "molecularly defined renal carcinomas". Novel entities included in the WHO 2022 classification are eosinophilic solid and cystic renal cell carcinoma (ESC RCC), anaplastic lymphoma kinase (ALK)-rearranged RCC and ELOC (formerly TCEB1)-mutated RCC. The category of "other renal tumours" includes a group of diverse, unrelated renal tumours that do not fit into other categories. The group of "molecularly defined renal carcinomas" reflects recent discoveries in the renal tumour genomics. These molecularly-defined renal entities demonstrate a set of morphologic features reflecting genotype-phenotype relationships. Final diagnosis of such entities rests on phenotypic and immunohistochemical (IHC) correlation, usually associated with IHC surrogate makers that reflect specific genetic abnormalities.

ALK rearranged renal cell carcinoma (ALK-RCC): a multi-institutional study of twelve cases with identification of novel partner genes CLIP1, KIF5B and KIAA1217.

ALK rearranged renal cell carcinoma (ALK-RCC) has recently been included in 2016 WHO classification as a provisional entity. In this study, we describe 12 ALK-RCCs from 8 institutions, with detailed clinical, pathological, immunohistochemical (IHC), fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) analyses. Patients' age ranged from 25 to 68 years (mean, 46.3 years). Seven patients were females and five were males (M:F = 1:1.4). Tumor size ranged from 17 to 70 mm (mean 31.5, median 25 mm). The pTNM stage included: pT1a (n = 7), pT1b (n = 1), and pT3a (n = 4). Follow-up was available for 9/12 patients (range: 2 to 153 months; mean 37.6 months); 8 patients were alive without disease and one was alive with distant metastases. The tumors demonstrated heterogeneous, 'difficult to classify' morphology in 10/12 cases, typically showing diverse architectural and cellular morphologies, including papillary, tubular, tubulocystic, solid, sarcomatoid (spindle cell), rhabdoid, signet-ring cell, and intracytoplasmic vacuoles, often set in a mucinous background. Of the remaining two tumors, one showed morphology resembling mucinous tubular and spindle cell renal cell carcinoma (MTSC RCC-like) and one was indistinguishable from metanephric adenoma. One additional case also showed a focal metanephric adenoma-like area, in an otherwise heterogeneous tumor. By IHC, all tumors were diffusely positive for ALK and PAX8. In both cases with metanephric adenoma-like features, WT1 and ALK were coexpressed. ALK rearrangement was identified in 9/11 tumors by FISH. ALK fusion partners were identified by NGS in all 12 cases, including the previously reported: STRN (n = 3), TPM3 (n = 3), EML4 (n = 2), and PLEKHA7 (n = 1), and also three novel fusion partners: CLIP1 (n = 1), KIF5B (n = 1), and KIAA1217 (n = 1). ALK-RCC represents a genetically distinct entity showing a heterogeneous histomorphology, expanded herein to include unreported metanephric adenoma-like and MTSC RCC-like variants. We advocate a routine ALK IHC screening for "unclassifiable RCCs" with heterogeneous features.

ESC, ALK, HOT and LOT: Three Letter Acronyms of Emerging Renal Entities Knocking on the Door of the WHO Classification.

Kidney neoplasms are among the most heterogeneous and diverse tumors. Continuous advancement of this field is reflected in the emergence of new tumour entities and an increased recognition of the expanding morphologic, immunohistochemical, molecular, epidemiologic and clinical spectrum of renal tumors. Most recent advances after the 2016 World Health Organization (WHO) classification of renal cell tumors have provided new evidence on some emerging entities, such as anaplastic lymphoma kinase rearrangement-associated RCC (ALK-RCC), which has already been included in the WHO 2016 classification as a provisional entity. Additionally, several previously unrecognized entities, not currently included in the WHO classification, have also been introduced, such as eosinophilic solid and cystic renal cell carcinoma (ESC RCC), low-grade oncocytic renal tumor (LOT) and high-grade oncocytic renal tumor (HOT) of kidney. Although pathologists play a crucial role in the recognition and classification of these new tumor entities and are at the forefront of the efforts to characterize them, the awareness and the acceptance of these entities among clinicians will ultimately translate into more nuanced management and improved prognostication for individual patients. In this review, we summarise the current knowledge and the novel data on these emerging renal entities, with an aim to promote their increased diagnostic recognition and better characterization, and to facilitate further studies that will hopefully lead to their formal recognition and consideration in the future classifications of kidney tumors.

Distinct DNA methylation alterations are associated with cribriform architecture and intraductal carcinoma in Gleason pattern 4 prostate tumors.

The aim of the present study was to explore DNA methylation aberrations in association with cribriform architecture and intraductal carcinoma (IDC) of the prostate, as there is robust evidence that these morphological features are associated with aggressive disease and have significant clinical implications. Herein, the associations of a panel of seven known prognostic DNA methylation biomarkers with cribriform and IDC features were examined in a series of 91 Gleason pattern (GP) 4 tumors derived from Gleason score 7 radical prostatectomies. Gene specific DNA methylation was compared between cribriform and/or IDC positive vs. negative cases, and in association with clinicopathological features, using Chi square and Mann-Whitney U tests. DNA methylation of the adenomatous polyposis coli, Ras association domain family member 1 and T-box 15 genes was significantly elevated in GP4 tumors with cribriform and/or IDC features compared with negative cases (P=0.045, P=0.007 and P=0.013, respectively). To the best of our knowledge, this provides the first evidence for an association between cribriform and/or IDC and methylation biomarkers, and warrants further investigation of additional DNA methylation events in association with various architectural patterns in prostate cancer.

Not all gleason pattern 4 prostate cancers are created equal: A study of latent prostatic carcinomas in a cystoprostatectomy and autopsy series.

BACKGROUND: The Gleason grading system represents the cornerstone of the management of prostate cancer. Gleason grade 4 (G4) is a heterogeneous set of architectural patterns, each of which may reflect a distinct prognostic value. METHODS: We determined the prevalence of the various G4 architectural patterns and intraductal carcinoma (IDC) in latent prostate cancer in contemporary Russian (n = 220) and Japanese (n = 100) autopsy prostates and in cystoprostatectomy (CP) specimens (n = 248) collected in Italy. We studied the association of each G4 pattern with extraprostatic extension (EPE) and tumor volume to gain insight into their natural history. Presence of IDC and nine architectural features of Gleason grade 4 and 5 cancer were recorded. RESULTS: The prevalence of Gleason score ≥ 7 PC was higher in the autopsy series (11%) compared to the CP series (6.5%, P = 0.04). The prevalence of IDC and carcinoma with a cribriform architecture was 2.2% and 3.4% in the autopsy series and 0.8% and 3.6% in the cystoprostatectomy series, respectively. In multivariable analysis, cribriform architecture was significantly associated with increased tumor volume (P < 0.001) and EPE (OR:11.48, 95%CI:2.30-57.16, P = 0.003). IDC was also significantly associated with EPE (OR:10.08, 95%CI:1.58-64.28, P = 0.014). Small fused glands had a strong negative association with EPE in the autopsy series (OR:0.06, 95%CI:0.01-0.58, P = 0.015). DISCUSSION: Our study revealed that in latent prostate cancer both cribriform architecture and IDC are uniquely associated with poor pathological outcome features. In contrast, Gleason score 7 (3 + 4) cancers with small-fused gland pattern might possibly include some prostate cancers with a more indolent biology.

Management of magnetic intravitreal foreign bodies in 71 eyes.

BACKGROUND AND OBJECTIVE: To evaluate the management of a series of eyes with magnetic intravitreal foreign bodies. PATIENTS AND METHODS: This retrospective review examined consecutive cases of ocular injury associated with intraocular foreign bodies; 71 eyes included had a single metallic intraocular foreign body (< 5 mm) located in the vitreous cavity removed by external magnet or intraocular forceps. Variables included preoperative and postoperative visual acuity, retinal break formation, retinal detachment, presence of an afferent pupillary defect, intraocular pressure, entrance site, foreign body size, method of extraction, and time between occurrence and surgical extraction. RESULTS: Factors predictive of good visual outcome (visual acuity > 20/200) were: shortest interval between trauma and foreign body extraction, preoperative visual acuity of 20/200 or better, and absence of afferent pupillary defect. CONCLUSIONS: In this nonrandomized study, good visual results could be obtained in eyes undergoing prompt foreign body removal, especially those with good preoperative visual acuity and no afferent pupillary defect.