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Anatomic imaging with contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) has long been the mainstay of renal mass characterization. However, those modalities are often unable to adequately characterize indeterminate, solid, enhancing renal masses - with some exceptions, such as the development of the clear-cell likelihood score on multi-parametric MRI. As such, molecular imaging approaches have gained traction as an alternative to anatomic imaging. Mitochondrial imaging with 99m Tc-sestamibi single-photon emission computed tomography/CT is a cost-effective means of non-invasively identifying oncocytomas and other indolent renal masses. On the other end of the spectrum, carbonic anhydrase IX agents, most notably the monoclonal antibody girentuximab - which can be labeled with positron emission tomography radionuclides such as zirconium-89 - are effective at identifying renal masses that are likely to be aggressive clear cell renal cell carcinomas. Renal mass biopsy, which has a relatively high non-diagnostic rate and does not definitively characterize many oncocytic neoplasms, nonetheless may play an important role in any algorithm targeted to renal mass risk stratification. The combination of molecular imaging and biopsy in selected patients with other advanced imaging methods, such as artificial intelligence/machine learning and the abstraction of radiomics features, offers the optimal way forward for maximization of the information to be gained from risk stratification of indeterminate renal masses. With the proper application of those methods, inappropriately aggressive therapy for benign and indolent renal masses may be curtailed., Competing Interests: Declaration of competing interest SPR is a consultant for, has equity in, and has received research funding from Precision Molecular, Inc. SPR and MAG are consultants for Lantheus. SPR and MAG are consultants for Telix. JDO has been a consultant for Telix., (Copyright © 2024 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Purposes: Low-grade oncocytic tumor (LOT) is a rare renal tumor that has emerged from the spectrum of eosinophilic/oncocytic renal tumors and poses a diagnostic challenge due to its similarity to chromophobe renal cell carcinoma (CHRCC) and renal oncocytoma (RO). The imaging features of this novel tumor entity have not yet been clearly described. The purpose of this study was to describe the imaging features of LOT with radiologic-pathologic correlation., Methods: We conducted a retrospective observational study involving two expert centers. We identified 12 pathologically proven LOT with preoperative imaging available, including at least computed tomography (CT) or magnetic resonance imaging (MRI), from the past 12 years. Three experienced radiologists performed the imaging analysis independently., Results: All tumors presented well-defined borders. Nine of the 12 LOT exhibited an early peripheral enhancement with complete or almost complete centripetal fill-in on nephrographic or delayed phases without any particular shape. Three showed a homogeneous contrast enhancement. Macroscopic fat and calcifications were not observed in any of the tumors., Conclusion: Early peripheral enhancement with complete or almost complete centripetal fill-in on nephrographic or delayed phases without any particular shape suggests a LOT diagnosis. Further analyses involving larger studies are needed to fully confirm these imaging characteristics. To date, a percutaneous biopsy should be performed before considering management., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Adrenocortical tumours are rare in children and account for only 0.3%-0.4% of all neoplasms in childhood. They present with variable signs and symptoms, depending on the type of hormonal hypersecretion. The majority of the adrenocortical tumours in children are functional (90%) and malignant (88%). Here, we describe a functional plurihormonal oncocytic adrenal cortical adenoma in a young girl, that mimicked a malignant adrenal lesion, clinically as well as on imaging and biochemical features. This report bears the objective of being aware of the atypical biochemical as well as imaging characteristics of oncocytic adrenal tumours., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: The 2022 World Health Organization classification of renal neoplasia expanded the spectrum of oncocytic neoplasms to encompass newly established and emerging entities; one of the latter is the low-grade oncocytic tumor (LOT). This study reports the radiologic appearance and clinical behavior of LOT., Methods: In this IRB-approved, HIPPA-compliant retrospective study, our institution's pathology database was searched for low-grade oncocytic tumors or neoplasms. Patient age, gender, and comorbidities were obtained from a review of electronic medical records, and imaging characteristics of the tumors were assessed through an imaging platform., Results: The pathology database search yielded 14 tumors in 14 patients. Four patients were excluded, as radiologic images were not available in three, and one did not fulfill diagnostic criteria after pathology re-review. The resulting cohort consisted of 10 tumors (median diameter 2.3 cm, range 0.7-5.1) in 10 patients (median age 68 years, range 53-91, six women). All tumors presented as a solitary, well-circumscribed, mass with solid components. All enhanced as much or almost as much as adjacent renal parenchyma; all but one enhanced heterogeneously. None had lymphadenopathy, venous invasion, or metastatic disease at presentation or at clinical follow-up (median, 22.2 months, range 3.4-71.6). Among five tumors undergoing active surveillance, mean increase in size was 0.4 cm/year at imaging follow-up (median 16.7 months, range 8.9-25.4)., Conclusion: LOT, a recently described pathologic entity in the kidney, can be considered in the differential diagnosis of an avidly and typically heterogeneously enhancing solid renal mass in an adult patient., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: Quantitative comparison of the diagnostic efficacy of conventional diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) in differentiating between chromophobe renal cell carcinoma (ChRCC) from renal oncocytoma (RO)., Methods: A total of 48 patients with renal tumours who had undergone DWI and IVIM were divided into two groups-ChRCC (n = 28) and RO (n = 20) groups, and the apparent diffusion coefficient (ADC), true diffusivity (D), pseudo-diffusion coefficient (D*), perfusion fraction (f) and their diagnostic efficacy were compared between the two groups., Results: The D* values were higher in the ChRCCs group compared to the RO groups (0.019 ± 0.003 mm2/s vs 0.008 ± 0.002 mm2/s, P < .05). Moreover, the ADC, D and f values were higher in ROs compared to ChRCCs (0.61 ± 0.08 × 10-3 mm2/s vs 0.51 ± 0.06 × 10-3 mm2/s, 1.02 ± 0.15 × 10-3 mm2/s vs 0.86 ± 0.07 × 10-3 mm2/s, 0.41 ± 0.05 vs 0.28 ± 0.02, P < .05). The areas of the ADC, D, D* and f values under the ROC curves in differentiating ChRCCs from ROs were 0.713, 0.839, 0.856 and 0.906, respectively. The cut-off values of ADC, D, D* and f were 0.54, 0.91, 0.013 and 0.31, respectively. The AUC, sensitivity, specificity and accuracy of the f values were 0.906, 89.3%, 80.0% and 89.6%, respectively. For pairwise comparisons of ROC curves and diagnostic efficacy, IVIM parameters, that is, D, D* and f offered better diagnostic accuracy than ADC in differentiating ChRCCs from ROs (P = .013, .016, and .008) with f having the highest diagnostic accuracy., Conclusion: IVIM parameters presented better performance than ADC in differentiating ChRCCs from ROs., Advances in Knowledge: (1) D* values of ChRCCs were higher, while ADC, D and f values were lower than those of RO tumours. (2) f values had the highest diagnostic efficacy in differentiating ChRCC from RO. (3) IVIM parameters, that is, D, D* and f offered better diagnostic accuracy than ADC in differentiating ChRCC from RO (P=.013, .016, and .008)., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Oncocytic lesions represent a group of benign and potentially precancerous tumors characterized by the accumulation of oncocytes, which are large, granular, and eosinophilic cells. Diagnosing oncocytic lesions in the parotid gland typically involves a combination of imaging techniques, such as ultrasound, Computed Tomography (CT) scans, and Magnetic Resonance Imaging (MRI). Fine-needle aspiration (FNA) biopsy with histopathological examination remains the primary diagnostic tool for these lesions. Accurate diagnosis is crucial for appropriate management decisions. Treatment options for oncocytic lesions in the parotid gland include surgery, conservative management, and radiation therapy (RT). However, in the head and neck region, radiation doses can be a double-edged sword. While RT is a treatment modality, low radiation doses can promote the development of oncocytic lesions in the parotid gland. The prognosis for patients with oncocytic lesions is generally favorable, especially when the lesions are benign and appropriately managed. Current research focuses on the molecular mechanisms underlying oncocytic lesions in response to low-dose radiation exposure. The development of these lesions following low radiation doses represents a significant clinical concern. This manuscript provides a comprehensive overview of the current knowledge regarding oncocytic lesions in the parotid gland, including risk factors, diagnosis, treatment options, and ongoing research, offering valuable insights for clinicians and researchers.

Background: Of the half a million cases of thyroid cancer diagnosed annually, 95% are differentiated thyroid cancers. Although clinical guidelines recommend surgical resection followed by radioactive iodine ablation, loss of sodium-iodine symporter expression causes up to 20% of differentiated thyroid cancers to become radioactive iodine refractory. For patients with radioactive iodine refractory disease, there is an urgent need for new diagnostic and therapeutic approaches. We evaluated the thyroid-stimulating hormone receptor as a potential target for imaging of differentiated thyroid cancer., Methods: We immunostained tissue microarrays containing 52 Hurthle cell carcinomas to confirm thyroid-stimulating hormone receptor expression. We radiolabeled chelator deferoxamine conjugated to recombinant human thyroid-stimulating hormone analog superagonist TR1402 with 89 Zr (t 1/2  = 78.4 h, β +  =22.7%) to produce [ 89 Zr]Zr-TR1402. We performed in vitro uptake assays in high-thyroid-stimulating hormone receptor and low-thyroid-stimulating hormone receptor-expressing THJ529T and FTC133 thyroid cancer cell lines. We performed in vivo positron emission tomography/computed tomography and biodistribution studies in male athymic nude mice bearing thyroid-stimulating hormone receptor-positive THJ529T tumors., Results: Immunohistochemical analysis revealed 62% of patients (27 primary and 5 recurrent) were thyroid-stimulating hormone receptor membranous immunostain positive. In vitro uptake of 1nM [ 89 Zr]Zr-TR1402 was 38 ± 17% bound/mg in thyroid-stimulating hormone receptor-positive THJ529T thyroid cancer cell lines compared to 3.2 ± 0.5 in the low-expressing cell line (P < .01), with a similar difference seen in FTC133 cell lines (P < .0001). In vivo and biodistribution studies showed uptake of [ 89 Zr]Zr-TR1402 in thyroid-stimulating hormone receptor-expressing tumors, with a mean percentage of injected dose/g of 1.9 ± 0.4 at 3 days post-injection., Conclusion: Our observation of thyroid-stimulating hormone receptor expression in tissue microarrays and [ 89 Zr]Zr-TR1402 accumulation in thyroid-stimulating hormone receptor-positive thyroid cancer cells and tumors suggests thyroid-stimulating hormone receptor is a promising target for imaging of differentiated thyroid cancer., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Technetium-99m-sestamibi single-photon emission CT/x-ray CT is an emerging clinical tool to differentiate oncocytic tumors from renal cell carcinomas. We report data from a large institutional cohort of patients who underwent technetium-99m-sestamibi scans during evaluation of renal masses., Materials and Methods: Patients who underwent technetium-99m-sestamibi single-photon emission CT/x-ray CT between February 2020 and December 2021 were included in the analysis. Scans were defined as "hot" for oncocytic tumor when technetium-99m-sestamibi uptake was qualitatively equivalent or higher between the mass of interest and normal renal parenchyma, suggesting oncocytoma, hybrid oncocytic/chromophobe tumor, or chromophobe renal cell carcinoma. Demographic, pathological, and management strategy data were compared between "hot" and "cold" scans. For individuals who underwent diagnostic biopsy or extirpative procedures, the concordance between radiological findings and pathology was indexed., Results: A total of 71 patients (with 88 masses) underwent technetium-99m-sestamibi imaging with 60 (84.5%) patients having at least 1 "cold" mass on imaging and 11 (15.5%) patients exhibiting only "hot" masses. Pathology was available for 7 "hot" masses, with 1 biopsy specimen (14.3%) being discordant (clear cell renal cell carcinoma). Five patients with "cold" masses underwent biopsy. Out of 5 biopsied masses, 4 (80%) were discordant oncocytomas. Of the extirpated specimens, 35/40 (87.5%) harbored renal cell carcinoma and 5/40 (12.5%) yielded discordant oncocytomas. In sum, 20% of pathologically sampled masses that were "cold" on technetium-99m-sestamibi imaging still harbored oncocytoma/hybrid oncocytic/chromophobe tumor/chromophobe renal cell carcinoma., Conclusions: Further work is needed to define utility of technetium-99m-sestamibi in real-world clinical practice. Our data suggest this imaging strategy is not yet ready to replace biopsy.

Objectives: We aimed to explore the diagnostic efficacy of MR texture analysis and imaging signs in the differentiation of renal oncocytoma from renal cell carcinoma (RCC)., Methods: From January 2015 to March 2019, a total of 168 localized solid renal masses (37 oncocytomas, 131 RCCs) were retrospectively included. Two radiologists reviewed complete MR images and recorded imaging presentation. Texture parameters were extracted from 3D ROIs on axial FSE-T2WI. Univariate and multivariate logistic regressions were used for feature selection and nomogram construction. The diagnostic performances were assessed by receiver operating characteristic (ROC) curves., Results: Cystic change, hemorrhage, SEI and four texture parameters significantly correlated with oncocytoma in the training cohort. For differentiating oncocytoma from RCC, the nomogram yielded an AUC of 0.874 in the training cohort and 0.830 in the testing cohort. For differentiating oncocytoma from chRCC, the nomogram had an AUC of 0.889 in the training cohort and 0.861 in the testing cohort. For differentiating oncocytoma from pRCC, the nomogram had an AUC of 0.932 in the training cohort and 0.792 in the testing cohort. For differentiating oncocytoma from ccRCC, the nomogram had an AUC of 0.829 in the training cohort and 0.813 in the testing cohort., Conclusion: The diagnostic nomogram combining MR texture parameters with imaging signs performed well in differentiating oncocytomas with localized RCC and its subtypes., Advances in Knowledge: Few articles reported using the combination of MR texture analysis with imaging signs in differentiating RCC from oncocytoma. Our study established a useful nomogram in subtype characterization., Competing Interests: Competing interestsOne of our author, Ms. Sicong Wang, works for GE Healthcare, China. She assisted in the texture parameter extraction and statistical analyzed. She and her company did not have any financial interest or conflict with our study. All the other authors have no conflicts of interesting.

Abstract: Preoperative differentiation of oncocytomas from renal cell carcinoma (RCC) is often challenging. 99m Tc-MIBI imaging could play a potential role in differentiating oncocytoma from RCC, which in turn could guide surgical decision-making. We present the use of 99m Tc-MIBI SPECT/CT to characterize a renal mass in a 66-year-old man with a complex medical history, including history of bilateral oncocytomas. 99m Tc-MIBI SPECT/CT showed features suspicious of a malignant tumor, which was confirmed postnephrectomy as a chromophobe and papillary RCC collision tumor. This case supports 99m Tc-MIBI imaging for preoperative differentiation of benign versus malignant renal tumors., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The differentiation of minimal-fat-or low-fat-angiomyolipomas from other renal lesions is clinically challenging in conventional computed tomography. In this work, we have assessed the potential of grating-based x-ray phase-contrast computed tomography (GBPC-CT) for visualization and quantitative differentiation of minimal-fat angiomyolipomas (mfAMLs) and oncocytomas from renal cell carcinomas (RCCs) on ex vivo renal samples., Materials and Methods: Laboratory GBPC-CT was performed at 40 kVp on 28 ex vivo kidney specimens including five angiomyolipomas with three minimal-fat (mfAMLs) and two high-fat (hfAMLs) subtypes as well as three oncocytomas and 20 RCCs with eight clear cell (ccRCCs), seven papillary (pRCCs) and five chromophobe RCC (chrRCC) subtypes. Quantitative values of conventional Hounsfield units (HU) and phase-contrast Hounsfield units (HUp) were determined and histogram analysis was performed on GBPC-CT and grating-based attenuation-contrast computed tomography (GBAC-CT) slices for each specimen. For comparison, the same specimens were imaged at a 3T magnetic resonance imaging (MRI) scanner., Results: We have successfully matched GBPC-CT images with clinical MRI and histology, as GBPC-CT presented with increased soft tissue contrast compared to absorption-based images. GBPC-CT images revealed a qualitative and quantitative difference between mfAML samples (58±4 HUp) and oncocytomas (44±10 HUp, p = 0.057) and RCCs (ccRCCs: 40±12 HUp, p = 0.012; pRCCs: 43±9 HUp, p = 0.017; chrRCCs: 40±7 HUp, p = 0.057) in contrast to corresponding laboratory attenuation-contrast CT and clinical MRI, although not all differences were statistically significant. Due to the heterogeneity and lower signal of oncocytomas, quantitative differentiation of the samples based on HUp or in combination with HUs was not possible., Conclusions: GBPC-CT allows quantitative differentiation of minimal-fat angiomyolipomas from pRCCs and ccRCCs in contrast to absorption-based imaging and clinical MRI., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Birnbacher et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background There is uncertainty in the management of renal masses diagnosed as oncocytomas with image-guided percutaneous biopsy. Purpose To assess the reliability of a diagnosis of oncocytoma based on image-guided percutaneous renal mass biopsy and evaluate patient outcomes following different management strategies. Materials and Methods In this retrospective study, image-guided percutaneous biopsy pathology reports from April 2004 to April 2019 were searched for keywords "oncocytoma" and "oncocytic neoplasm" and compared with surgical pathology or repeat biopsy results. Patients with at least 12 months of clinical follow-up and known cause of death were grouped according to management strategies, and disease-specific survival and metastatic renal cell carcinoma (RCC)-free survival were compared. Mass growth rates were calculated with use of a normal linear mixed model. Results The database yielded 160 biopsy reports of 149 renal masses in 139 patients; 149 masses were categorized as oncocytoma ( n = 107), likely oncocytoma ( n = 12), oncocytic neoplasm ( n = 28), and indeterminate with oncocytoma in differential ( n = 2). Biopsied masses categorized as oncocytoma or likely oncocytoma were oncocytomas in 16 of 17 masses (94%) based on surgical pathology or repeat biopsy; four of eight masses (50%) categorized as oncocytic neoplasms were low-grade RCCs. Outcome analysis included 121 patients (mean age ± SD, 68 years ± 9.1; 82 men); 80 patients initially underwent active surveillance (11 were later treated), 33 underwent ablation, and eight underwent surgery. Disease-specific survival and metastatic-free survival were 100% after each management strategy (median follow-up, 86.6 months; range, 14.2-207.9 months). Mass growth rate (mean, 1.7 mm per year) showed no evidence of a significant difference among biopsy result categories ( P = .37) or initial ( P = .84) or final management strategies ( P = .11). Conclusion Image-guided percutaneous biopsy diagnosis of renal oncocytoma was reliable. Although some masses diagnosed as oncocytic neoplasms were low-grade renal cell carcinomas (RCCs) at final diagnosis, no patients died of RCC, including those managed with active surveillance. © RSNA, 2023 See also the editorial by Lockhart in this issue.

Purpose: To explore the utility of four-phase computed tomography (CT) in distinguishing renal oncocytoma with central hypodense areas from clear cell renal cell carcinoma (ccRCC)., Methods: Eighteen patients with oncocytoma and 63 patients with ccRCC presenting with central hypodense areas were included in this study. All patients underwent four-phase CT imaging including the excretory phases later than 20 min after contrast injection. Two blinded experienced radiologists visually reviewed the enhancement features of the central hypodense areas in the excretory phase images and selected the area demonstrating the greatest degree of enhancement of the tumor in the corticomedullary phase images. Regions of interest (ROIs) were placed in the same location in each of the three contrast-enhanced imaging phases. Additionally, ROIs were placed in the adjacent normal renal cortex for normalization. The ratio of the lesion to cortex attenuation (L/C) for the three contrast-enhanced imaging phases and absolute de-enhancement were calculated. The receiver operating characteristic curve was used to obtain the cut-off values., Results: Complete enhancement inversion of the central areas was observed in 12 oncocytomas (66.67%) and 16 ccRCCs (25.40%) ( P = 0.003). Complete enhancement inversion combined with L/C in the corticomedullary phase lower than 1.0 ( P < 0.001) or absolute de-enhancement lower than 42.5 HU ( P < 0.001) provided 86.42% and 85.19% accuracy, 61.11% and 55.56% sensitivity, 93.65% and 93.65% specificity, 73.33% and 71.43% positive predictive value (PPV), and 89.39% and 88.06% negative predictive value (NPV), respectively, for the diagnosis of oncocytomas. Combined with complete enhancement inversion, L/C in the corticomedullary phase lower than 1.0 and absolute de-enhancement lower than 42.5 HU provided 87.65%, 55.56%, 96.83%, 83.33%, and 88.41% of accuracy, sensitivity, specificity, PPV, and NPV, respectively, for the diagnosis of oncocytomas., Conclusion: The combination of enhancement features of the central hypodense areas and the peripheral tumor parenchyma can help distinguish oncocytoma with central hypodense areas from ccRCC.

Background: Radiomics is a type of quantitative analysis that provides a more objective approach to detecting tumor subtypes using medical imaging. The goal of this paper is to conduct a comprehensive assessment of the literature on computed tomography (CT) radiomics for distinguishing renal cell carcinomas (RCCs) from oncocytoma., Methods: From February 15th 2012 to 2022, we conducted a broad search of the current literature using the PubMed/MEDLINE, Google scholar, Cochrane Library, Embase, and Web of Science. A meta-analysis of radiomics studies concentrating on discriminating between oncocytoma and RCCs was performed, and the risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies method. The pooled sensitivity, specificity, and diagnostic odds ratio were evaluated via a random-effects model, which was applied for the meta-analysis. This study is registered with PROSPERO (CRD42022311575)., Results: After screening the search results, we identified 6 studies that utilized radiomics to distinguish oncocytoma from other renal tumors; there were a total of 1064 lesions in 1049 patients (288 oncocytoma lesions vs 776 RCCs lesions). The meta-analysis found substantial heterogeneity among the included studies, with pooled sensitivity and specificity of 0.818 [0.619-0.926] and 0.808 [0.537-0.938], for detecting different subtypes of RCCs (clear cell RCC, chromophobe RCC, and papillary RCC) from oncocytoma. Also, a pooled sensitivity and specificity of 0.83 [0.498-0.960] and 0.92 [0.825-0.965], respectively, was found in detecting oncocytoma from chromophobe RCC specifically., Conclusions: According to this study, CT radiomics has a high degree of accuracy in distinguishing RCCs from RO, including chromophobe RCCs from RO. Radiomics algorithms have the potential to improve diagnosis in scenarios that have traditionally been ambiguous. However, in order for this modality to be implemented in the clinical setting, standardization of image acquisition and segmentation protocols as well as inter-institutional sharing of software is warranted., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Published by Elsevier Inc.)

Background: Although the central scar is an essential imaging characteristic of renal oncocytoma (RO), its utility in distinguishing RO from renal cell carcinoma (RCC) has not been well explored. The study aimed to evaluate whether the combination of CT characteristics of the peripheral tumor parenchyma (PTP) and central hypodense area (CHA) can differentiate typical RO with CHA from RCC., Methods: A total of 132 tumors on the initial dataset were retrospectively evaluated using four-phase CT. The excretory phases were performed more than 20 min after the contrast injection. In corticomedullary phase (CMP) images, all tumors had CHAs. These tumors were categorized into RO (n = 23), clear cell RCC (ccRCC) (n = 85), and non-ccRCC (n = 24) groups. The differences in these qualitative and quantitative CT features of CHA and PTP between ROs and ccRCCs/non-ccRCCs were statistically examined. Logistic regression filters the main factors for separating ROs from ccRCCs/non-ccRCCs. The prediction models omitting and incorporating CHA features were constructed and evaluated, respectively. The effectiveness of the prediction models including CHA characteristics was then confirmed through a validation dataset (8 ROs, 35 ccRCCs, and 10 non-ccRCCs)., Results: The findings indicate that for differentiating ROs from ccRCCs and non-ccRCCs, prediction models with CHA characteristics surpassed models without CHA, with the corresponding areas under the curve (AUC) being 0.962 and 0.914 versus 0.952 and 0.839 respectively. In the prediction models that included CHA parameters, the relative enhancement ratio (RER) in CMP and enhancement inversion, as well as RER in nephrographic phase and enhancement inversion were the primary drivers for differentiating ROs from ccRCCs and non-ccRCCs, respectively. The prediction models with CHA characteristics had the comparable diagnostic ability on the validation dataset, with respective AUC values of 0.936 and 0.938 for differentiating ROs from ccRCCs and non-ccRCCs., Conclusion: The prediction models with CHA characteristics can help better differentiate typical ROs from RCCs. When a mass with CHA is discovered, particularly if RO is suspected, EP images with longer delay scanning periods should be acquired to evaluate the enhancement inversion characteristics of CHA., (© 2023. The Author(s).)

Purposes: To determine the CT features and demographic data predictive of type 2 papillary renal cell carcinoma (PRCC) that can help distinguish this neoplasm from fat-poor angiomyolipoma (fpAML) and oncocytoma., Methods: Fifty-four patients with type 2 PRCC, 48 with fpAML, and 47 with oncocytoma in the kidney from multiple centers were retrospectively reviewed. The demographic data and CT features of type 2 PRCC were analyzed and compared with those of fpAML and oncocytoma by univariate analysis and multiple logistic regression analysis to determine the predictive factors for differential diagnosis. Then, receiver operating characteristic (ROC) curve analysis was performed to further assess the logistic regression model and set the threshold level values of the numerical parameters., Results: Older age (≥ 46.5 years), unenhanced lesion-to-renal cortex attenuation (RLRCA) < 1.21, corticomedullary ratio of lesion to renal cortex net enhancement (RLRCNE) < 0.32, and size ≥ 30.1 mm were independent predictors for distinguishing type 2 PRCC from fpAML (OR 14.155, 8.332, and 57.745, respectively, P < 0.05 for all). The area under the curve (AUC) of the multiple logistic regression model in the ROC curve analysis was 0.970. In the combined evaluation, the four independent predictors had a sensitivity and specificity of 0.896 and 0.889, respectively. A corticomedullary RLRCNE < 0.61, irregular shape, and male sex were independent predictors for the differential diagnosis of type 2 PRCC from oncocytoma (OR 15.714, 12.158, and 6.175, respectively, P < 0.05 for all). In the combined evaluation, the three independent predictors had a sensitivity and specificity of 0.889 and 0.979, respectively. The AUC of the multiple logistic regression model in the ROC curve analysis was 0.964., Conclusion: The combined application of CT features and demographic data had good ability in distinguishing type 2 PRCC from fpAML and oncocytoma, respectively., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Aim: To develop a predictive model to discriminate renal oncocytoma (RO) from chromophobe renal carcinoma (chRCC) using multiphase computed tomography (CT)., Materials and Methods: Two hundred and five cases of renal tumours were analysed retrospectively regarding attenuation values during four CT phases, in addition to age, size, and sex. Then, logistic analysis was applied and a nomogram model developed to predict the most significant variables that can be used to differentiate between both tumour types. The cases were histopathologically proven as 81 cases of RO and 124 cases of chRCC., Results: There was no association between the sex of the patient and the tumour types (p=0.41); however, there was a significant positive association between RO and the age of the patient (odds ratio 1.05; 95% confidence interval 1.02-1.08; p=0.001)) and a significant negative association between tumour size and RO (odds ratio 0.81; 95% confidence interval 73-90; p<0.001). There was a significant difference between tumour types in the contrast-enhanced phases. Logistic regression showed that absolute arterial enhancement (AAE) and absolute venous enhancement (AVE) are the most significant predictors for discriminating between tumour types. Combining these variables, size, AAE, and AVE were the best classifiers to discriminate between tumour types with an area under the curve of 0.90. A nomogram model was developed using these variables to predict RO probability in different case scenarios., Conclusion: The nomogram can predict the probability of RO from chRCC by using the best predictors, size, AAE, and AVE, with high accuracy., (Copyright © 2022 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background:  Tumors arising from the posterior pituitary gland are rare and closely resemble pituitary adenoma in presentation and imaging. Most of them come as a histopathologic surprise. We have analyzed the posterior pituitary tumors managed in our institute and have discussed the dilemmas in imaging, challenges in intraoperative squash cytology, and surgical management., Methods:  We retrospectively reviewed our operative database of pituitary tumors over the past 10 years, which included five posterior pituitary tumors (three granular cell tumors [GCTs] and two spindle cell oncocytomas [SCOs]). Clinical, imaging, and endocrine characteristics; intraoperative details; histopathologic features; and postoperative outcomes were collected and analyzed., Results:  The mean age of the patients was 47 years. All patients presented with varying degrees of vision loss. Radiology revealed a sellar / suprasellar lesion with the pituitary gland seen separately in two of three GCTs, whereas a separate pituitary gland could not be identified in both the SCOs. Pituitary adenoma was a radiologic diagnosis in only two of five cases. Three patients underwent a transsphenoidal surgery, whereas two underwent surgery by the transcranial approach. Intraoperative cytology was challenging, though a possibility of posterior pituitary tumor was considered in three of four cases, whereas one was considered meningioma. All the tumors were very vascular and influenced the extent of resection., Conclusions:  GCTs and SCOs are relatively uncommon tumors that are difficult to diagnose on preoperative imaging. Intraoperative squash cytology too can pose challenges. A preoperative suspicion can prepare the surgeon for surgery of these hypervascular tumors. The transcranial approach may be necessary in cases of uncertainty in imaging., Competing Interests: None declared., (Thieme. All rights reserved.)

Oncocytomas are benign tumors, with the classic stellate scar found in up to a third of cases, mainly in large ones. We present the case of a 69-year-old man with a palpable, mobile, and painless mass on the right flank, where abdominal ultrasound and abdominal computed tomography detected the presence of a solid right kidney lesion with a central stellate area in the sinus. Postoperative histological analysis confirmed the presence of oncocytoma with a central stellate scar. Biopsy may not be useful to distinguish this entity from renal carcinoma, surgery being necessary for definitive confirmation of the diagnosis of oncocytoma.

Purpose of Review: The aim of the review is to provide an update on the current and evolving approaches to diagnosing the challenging clinical entity of renal oncocytoma., Recent Findings: Renal oncocytoma is being increasingly recognized among patients with renal masses, and it can be found in up to 50% of benign small renal masses (SRMs) less than 4 cm. Renal oncocytomas have benign clinical biology but distinguishing them from some of the other renal masses with more malignant potential can be challenging due to overlapping imaging, histologic, and immunophenotypic characteristics. Increasing integration of various imaging modalities, histologic characteristics, cytogenetics, and molecular and metabolic signatures is helping better define and characterize renal masses., Summary: Evolving and complementary diagnostic approaches, including at the molecular level, are continuing to help refine the classification of renal tumors, with implications on their clinical behavior and ultimately clinical management., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Renal oncocytomas are rare benign epithelial tumors of the kidney. However, they are easily misdiagnosed as renal cancers, resulting in unnecessary radical nephrectomy. This review summarizes the use of ultrasound for the diagnosis of renal oncocytomas. On two-dimensional grayscale ultrasound, renal oncocytomas appear as solid, well-defined, round or oval, and relatively isoechoic or slightly hyperechoic masses. On color Doppler flow imaging, the "spoke-wheel" sign is evident. On power Doppler flow imaging, renal oncocytomas show mixed penetrating and peripheral patterns. Renal oncocytomas usually appear as highly enhanced on contrast-enhanced ultrasound images, and irregular nonenhanced areas in larger tumors. This review will help sonographers recognize renal oncocytomas., (© 2021. The Author(s), under exclusive licence to The Japan Society of Ultrasonics in Medicine.)

Objective: Differentiation between renal oncocytoma (RON) and chromophobe renal cell carcinoma (chRCC) remains challenging. We aimed to assess the accurate apparent diffusion coefficient (ADC) radiomics features in differentiating these tumors., Materials and Methods: This single-center retrospective study included 14 patients with histopathologically proven RON (n = 6) and chRCC (n = 8) who underwent magnetic resonance imaging. Features were extracted from ADC maps. Features with an intraclass correlation coefficient >0.90, an intergroup p < 0.01 and interrater differences with normal distribution underwent agreement and receiver operating characteristic curve analyses., Results: Overall, 6 features qualified for further analysis and Bland-Altman plots revealed acceptable agreement for all. Only 1 first order feature and 5 high order texture features successfully predicted RON with more than 90% sensitivities and specificities more than 80%., Conclusion: Squared mean ADC and certain gray level run length matrix features extracted by radiomics of ADC mapping provide quite high diagnostic precision in terms of distinguishing between RON and chRCC., (Copyright © 2021 AEU. Published by Elsevier España, S.L.U. All rights reserved.)

BACKGROUND The co-occurrence of renal oncocytoma and angiomyolipoma is exceedingly rare. To date, 17 such cases have been reported in the literature. This report describes a unique case of that association that presented as a single renal mass on imaging. CASE REPORT A 75-year-old woman presented with epigastric discomfort. A CT scan of the abdomen revealed a 6.6×5.7×4.7 cm enhancing right renal mass. Gross examination revealed a nodular, well-circumscribed, tan-brown mass located in the lower pole of the kidney that was abutting the renal capsule. Interestingly, superior to this mass, there was an adjacent, pale tan-white, firm, well-circumscribed nodule in the mid-pole, which was not detected on the CT scan and grossly extended to 1.1 cm of the overlying renal capsule. Histologically, the larger tumor showed characteristic features of oncocytoma. The smaller tumor had an admixture of mature adipose tissue, smooth muscle, and vessels, consistent with a renal angiomyolipoma. CONCLUSIONS We present a new case of synchronous renal angiomyolipoma and oncocytoma, which were uniquely adjacent and coexisted with minimal intermingling renal parenchyma. Other "eosinophilic renal tumors" are significant differential diagnosis considerations. Due to the close proximity of these lesions, this association can present clinically and radiologically as a single renal mass. Careful examination of the nephrectomy specimen is essential for the proper detection of small-sized tumors.

Background: Renal oncocytoma (RO) and chromophobe renal cell carcinoma (chRCC) have a common cellular origin and different clinical management and prognosis., Purpose: To explore the utility of computed tomography (CT) in the differentiation of RO and chRCC., Material and Methods: Twenty-five patients with RO and 73 patients with chRCC presenting with the central scar were included retrospectively. Two experienced radiologists independently reviewed the CT imaging features, including location, tumor size, relative density ratio, segmental enhancement inversion (SEI), necrosis, and perirenal fascia thickening, among others. Interclass correlation coefficient (ICC, for continuous variables) or Kappa coefficient test (for categorical variables) was used to determine intra-observer and inter-observer bias between the two radiologists., Results: The inter- and intra-reader reproducibility of the other CT imaging parameters were nearly perfect (>0.81) except for the measurements of fat (0.662). RO differed from chRCC in the cortical or medullary side ( P  = 0.005), relative density ratio ( P  = 0.020), SEI ( P  < 0.001), and necrosis ( P  = 0.045). The logistic regression model showed that location (right kidney), hypo-density on non-enhanced CT, SEI, and perirenal fascia thickening were highly predictive of RO. The combined indicators from logistic regression model were used for ROC analysis. The area under the ROC curve was 0.923 ( P  < 0.001). The sensitivity and specificity of the four factors combined for diagnosing RO were 88% and 86.3%, respectively. The correlation coefficient between necrosis and tumor size in all tumors including both of RO and chRCC was 0.584, indicating a positive correlation ( P  < 0.001)., Conclusion: The CT imaging features of location (right kidney), hypo-density on non-enhanced CT, SEI, and perirenal fascia thickening were valuable indicators in distinguishing RO from chRCC.

Background and Objectives : Renal Cell Carcinoma (RCC) accounts for 85% and oncocytomas constitute 3-7% of solid renal masses. Oncocytomas can be confused, especially with hypovascular RCC. The purpose of this research was to evaluate the contribution of diffusion-weighted imaging (DWI) and contrast-enhanced MRI sequences in the differential diagnosis of RCC and oncocytoma Materials and Methods : 465 patients with the diagnosis of RCC and 45 patients diagnosed with oncocytoma were retrospectively reviewed between 2009 to 2020. All MRI acquisitions were handled by a 1.5 T device (Achieva, Philips Healthcare, Best, The Netherlands) and all images were evaluated by the consensus of two radiologists with 10-15 years' experience. The SPSS package program version 15.0 software was used for statistical analysis of the study. Chi-square test, Mann-Whitney U test or the Kruskal-Wallis tests were used in the statistical analysis. A receiver operating characteristic (ROC) curve was used to calculate the cut-off values Results : The results were evaluated with a 95% confidence interval and a significance threshold of p < 0.05. ADC values ( p < 0.001) and enhancement index ( p < 0.01) were significantly lower in the RCC group than the oncocytoma group. Conclusion : DWI might become an alternative technique to the contrast-enhanced MRI in patients with contrast agent nephropathy or with a high risk of nephrogenic systemic fibrosis, calculation of CI of the oncocytoma and RCCs in the contrast-enhanced acquisitions would contribute to the differential diagnosis.

Objective: Pre-operative differentiation between renal oncocytoma (RO) and chromophobe renal cell carcinoma (chRCC) is critical due to their different clinical behavior and different clinical treatment decisions. The aim of this study was to develop and validate a CT-based radiomics nomogram for the pre-operative differentiation of RO from chRCC., Methods: A total of 141 patients (84 in training data set and 57 in external validation data set) with ROs ( n = 47) or chRCCs ( n = 94) were included. Radiomics features were extracted from tri-phasic enhanced-CT images. A clinical model was developed based on significant patient characteristics and CT imaging features. A radiomics signature model was developed and a radiomics score (Rad-score) was calculated. A radiomics nomogram model incorporating the Rad-score and independent clinical factors was developed by multivariate logistic regression analysis. The diagnostic performance was evaluated and validated in three models using ROC curves., Results: Twelve features from CT images were selected to develop the radiomics signature. The radiomics nomogram combining a clinical factor (segmental enhancement inversion) and radiomics signature showed an AUC value of 0.988 in the validation set. Decision curve analysis revealed that the diagnostic performance of the radiomics nomogram was better than the clinical model and the radiomics signature., Conclusions: The radiomics nomogram combining clinical factors and radiomics signature performed well for distinguishing RO from chRCC., Advances in Knowledge: Differential diagnosis between renal oncocytoma (RO) and chromophobe renal cell carcinoma (chRCC) is rather difficult by conventional imaging modalities when a central scar was present.A radiomics nomogram integrated with the radiomics signature, demographics, and CT findings facilitates differentiation of RO from chRCC with improved diagnostic efficacy.The CT-based radiomics nomogram might spare unnecessary surgery for RO.

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Purpose: To assess the ability to discriminate oncocytoma from RCC based on a model using whole tumor ADC histogram parameters with additional use of tumor volume and patient characteristics., Method: In this prospective study, 39 patients (mean age 65 years, range 28-79; 9/39 (23%) female) with 39 renal tumors (32/39 (82%) RCC and 7/39 (18%) oncocytoma) underwent multiparametric MRI between November 2014 and June 2018. Two regions of interest (ROIs) were drawn to cover both the entire tumor volume and a part of healthy renal cortex. ROI ADC maps were calculated using a mono-exponential model and ADC histogram distribution parameters were calculated. A logistic regression model was created using ADC histogram parameters, radiographic and patient characteristics that were significantly different between oncocytoma and RCC. A ROC curve of the model was constructed and the AUC, sensitivity and specificity were calculated. Furthermore, differences in intra-patient ADC histogram parameters between renal tumor and healthy cortex were calculated. A separate ROC curve was constructed to differentiate oncocytoma from RCC using statistically significant intra-patient parameter differences., Results: ADC standard deviation (p = 0.008), entropy (p = 0.010), tumor volume (p = 0.012), and patient sex (p = 0.018) were significantly different between RCC and oncocytoma. The regression model of these parameters combined had an ROC-AUC of 0.91 with a sensitivity of 86% and specificity of 84%. Intra-patient difference in ADC 25th percentile (p < 0.01) and entropy (p = 0.030) combined had a ROC-AUC of 0.86 with a sensitivity and specificity of 86%, and 81%, respectively., Conclusion: A model combining ADC standard deviation and entropy with tumor volume and patient sex has the highest diagnostic value for discrimination of oncocytoma. Although less accurate, intra-patient difference in ADC 25th percentile and entropy between renal tumor and healthy cortex can also be used. Although the results of this preliminary study do not yet justify clinical use of the model, it does stimulate further research using whole tumor ADC histogram parameters., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Parotid gland oncocytoma (PGO) is a rare benign epithelial tumor that usually occurs in the elderly population. The most common clinical presentation is a painless, slow-growing, non-tender, lobulated, and mobile mass. Histologically, it is composed of monotonous sheets of epithelial cells (oncocytes) with a central scar. The cross-sectional appearance is not specific, and it overlaps with other parotid lesions. On ultrasound (US), oncocytoma appears as an ovoid, well-defined, homogeneous, and hypoechoic lesion. Cystic and hemorrhagic areas as well as intralesional fat may be observed. Doppler analysis shows intratumoral vessels, sometimes with a spoke-wheel pattern. The peak systolic flow is high (up to 100 cm/sec). Furthermore, oncocytoma is avid of FDG on a PET scan, as well as a malignant tumor. Thus, a combined clinical, imaging, and pathologic assessment is essential to establish the most accurate diagnosis and plan the best treatment. US, combined with Doppler techniques, can play an important role in suggesting the diagnosis and confirming it through percutaneous sampling. The purpose of this review is to show the imaging findings in PGO, with special emphasis on the US appearance., (© 2020. Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB).)

Purpose: To investigate the diagnostic performance of a deep convolutional neural network for differentiation of clear cell renal cell carcinoma (ccRCC) from renal oncocytoma., Methods: In this retrospective study, 74 patients (49 male, mean age 59.3) with 243 renal masses (203 ccRCC and 40 oncocytoma) that had undergone MR imaging 6 months prior to pathologic confirmation of the lesions were included. Segmentation using seed placement and bounding box selection was used to extract the lesion patches from T2-WI, and T1-WI pre-contrast, post-contrast arterial and venous phases. Then, a deep convolutional neural network (AlexNet) was fine-tuned to distinguish the ccRCC from oncocytoma. Five-fold cross validation was used to evaluate the AI algorithm performance. A subset of 80 lesions (40 ccRCC, 40 oncocytoma) were randomly selected to be classified by two radiologists and their performance was compared to the AI algorithm. Intra-class correlation coefficient was calculated using the Shrout-Fleiss method., Results: Overall accuracy of the AI system was 91% for differentiation of ccRCC from oncocytoma with an area under the curve of 0.9. For the observer study on 80 randomly selected lesions, there was moderate agreement between the two radiologists and AI algorithm. In the comparison sub-dataset, classification accuracies were 81%, 78%, and 70% for AI, radiologist 1, and radiologist 2, respectively., Conclusion: The developed AI system in this study showed high diagnostic performance in differentiation of ccRCC versus oncocytoma on multi-phasic MRIs., (Copyright © 2021. Published by Elsevier Inc.)

Introduction: The management of follicular (FN) and Hurthle cell neoplasms (HCN) is often difficult because of the uncertainty of malignancy risk. We aimed to assess characteristics of benign and malignant follicular and Hurthle neoplasms based on their shape and size., Materials and Methods: Patients with Follicular adenoma (FA) or carcinoma (FC) and Hurthle Cell adenoma (HCA) or carcinoma (HCC) who had preoperative ultrasonography were included. Demographic data were retrieved. Size and shape of the nodules were measured. Logistic regression analyses and odds ratios were performed., Results: A total of 115 nodules with 57 carcinomas and 58 adenomas were included. Logistic regression analysis shows that the nodule height and the patient age are predictors of malignancy (p-values = 0.001 and 0.042). A cutoff value of nodule height ≥ 4 cm. produces an odds ratio of 4.5 (p-value = 0.006). An age ≥ 55 year-old demonstrates an odds ratio of 2.4-3.6 (p-value = 0.03). Taller-than-wide shape was not statistically significant (p-value = 0.613)., Conclusion: FC and HCC are larger than FA and HCA in size, with a cutoff at 4 cm. Increasing age increases the odds of malignancy with a cutoff at 55 year-old. Taller-than-wide shape is not a predictor of malignancy.

Objectives: We previously noted that the aorta-lesion-attenuation difference (ALAD) determined on CT scan discriminated well between chromophobe RCC and oncocytoma. The current evaluation seeks to validate these initial findings in a second cohort of nephrectomy patients., Methods: A retrospective review of preoperative CT scans and surgical pathology was performed on patients undergoing nephrectomy for small, solid renal masses. ALAD was calculated by measuring the difference in Hounsfield units (HU) between the aorta and the lesion of interest on the same image slice on preoperative CT scan. The discriminative ability of ALAD to differentiate malignant pathology from oncocytoma was evaluated by sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve (AUC) using ROC analysis., Results: Twenty-one preoperative CT scans and corresponding pathology reports were reviewed and included in the validation cohort. ALAD values were calculated during the excretory and nephrographic phases. Compared to the training cohort, patients in the validation cohort were significantly older (62 versus 59 years old), had larger tumors (3.7 versus 2.7 cm), and higher stage disease (59% versus 79% T1a disease). Nephrographic ALAD was able to differentiate malignant pathology from oncocytoma in the training and validation cohorts with a sensitivity of 84% versus 73%, specificity of 86% and 67%, PPV of 98% versus 91%, and NPV of 33% versus 35%. The AUC for malignant pathology versus oncocytoma in the validation cohort was 0.72 (95% CI 0.63-0.82). Nephrographic ALAD was able to differentiate chromophobe RCC from oncocytoma in the training and validation cohorts with a sensitivity of 100% versus 67%, specificity of 86% versus 67%, PPV of 75% versus 43%, and NPV of 100% versus 84%. The AUC for chromophobe RCC versus oncocytoma in the validation cohort was 0.72 (95% CI 0.48-0.96)., Conclusions: The ability of ALAD to discriminate between chromophobe RCC and oncocytoma was diminished in the validation cohort compared to the training cohort, but remained significant. The current findings support further investigation in the role of ALAD in the management of patients with indeterminate diagnoses of oncocytic neoplasm.

Purpose: To evaluate the ability of inferior vena cava-lesion-attenuation-difference (ILAD) and lesion-cortex-attenuation-ratio (LCAR) to differentiate renal oncocytomas (RO) from chromophobe renal cell carcinomas (chRCC)., Methods: Retrospective study with analysis of 84 cases of chRCC and 30 cases of RO confirmed by surgical pathology. ILAD was calculated by measuring the difference in Hounsfield units (HU) between the inferior vena cava and the lesion of interest on the same image slice on preoperative CT scan. Calculating LCAR using the CT attenuation ratio of lesion to renal cortex at the same image slice. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic values of ILAD and LCAR for disease activity., Results: There were no statistically significant differences in demographic and lesion characteristics between patients with chRCC and RO (p > 0.05). ILAD has significant statistical differences in the identification of RO and chRCC in the arterial (p = 0.031), venous (p = 0.047), and delayed phase (p = 0.002). And LCAR showed a statistically significant difference between two lesions during the arterial (p = 0.043), venous (p = 0.026), and delayed phase (p = 0.008). When all significant variables were used in combination to build a predicting model (Mix), the AUC was 0.871 (95% CI 0.759-0.984) with 67.9% sensitivity and 100% specificity., Conclusion: ILAD and LCAR at the arterial phase, venous phase and delayed phase were shown to be useful CT attenuation parameter in discriminating RO from chRCC when histologic evaluation on biopsy is indeterminate.

Abstract: Oncocytomas in the parotid gland are a rare benign neoplasm composed of mitochondrial-rich oncocytes. Here we present the case of an 85-year-old man with a history of biopsy-proven right parotid gland oncocytoma who underwent 99mTc-sestamibi scintigraphy and SPECT/CT in the context of primary hyperparathyroidism. Focal intense uptake of radiotracer is detected within the right parotid gland on sestamibi scintigraphy. SPECT/CT confirms the localization of sestamibi uptake to the hyperattenuating parotid gland oncocytoma., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The risk of malignancy (RoM) of indeterminate thyroid nodules (ITNs) shows a high variability in interinstitutional cohorts. The RoM is partially associated with the cytological degree of atypia and the ultrasound (US) pattern. This study evaluated the cancer risk of ITNs by jointly considering the cytological subcategory and the American Thyroid Association (ATA)-based US risk classification. Methods: This study features a retrospective cohort from two Brazilian centers comprising 238 ITNs with confirmed outcomes. US classification, according to ATA-based guidelines, and cytological subcategorization were determined. The cytological subgroups were as follows: (1) nuclear atypia (NA) related to papillary thyroid carcinoma (PTC) but insufficient to categorize the cytology as suspicious for malignancy; (2) architectural atypia without NA (AA); (3) both architectural and nuclear atypia (ANA); (4) oncocytic pattern (OP) without NA; and (5) NA not related to PTC (NANP). NA was divided into three subgroups: nuclear size and shape, nuclear membrane appearance, and/or chromatin aspects. Results: The overall frequency of malignancy was 39.5%. Among the cytological subcategories, the highest RoM was related to the NA (43.9%) and to the ANA (43.5%), followed by AA (29.4%), and OP (9.4%). NA was positively and independently associated with cancer (odds ratio [OR]: 4.5; confidence interval [CI: 1.2-16.6]) as was the occurrence of ANA (OR 6.6 [CI 1.5-29.5]). AA and OP were not independently associated with cancer. Both ATA-based high- and intermediate-risk categories showed an independent association with cancer (OR 6.8 [CI 2.9-15.5] and OR: 2.6 [CI 1.1-5.8], respectively). ITNs with cytological findings of NA or ANA when combined with intermediate US patterns had RoM values of 47.5% and 56.7%, respectively. Both cytological subcategories, when combined with the ATA high-suspicion class reached an RoM >70%. The type of NA with the highest odds for cancer was related to the nuclear membrane (OR 11.5). Conclusions: The RoM of ITNs can reach almost 80% when both NA and ATA-based high-risk US features are present. The presence of such cytological features also increased the RoM in the ATA-based intermediate-risk US category. In addition, AA and OP were not independently related to higher cancer risk. These results strengthen the recommendations for combing cytological subcategorization and US risk classification in the workup for ITNs before the decision of a molecular testing, clinical observation, or diagnostic surgery.

Background: Refining the risk of malignancy in patients presenting with thyroid nodules with indeterminate cytology (IC) is a critical challenge. We investigated the performances of 18 F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) to predict malignancy. Methods: Between May 2016 and March 2019, 107 patients presenting with a thyroid nodule ≥15 mm with IC and eligible for surgery were included in this prospective study. Head-and-neck PET/CT acquisitions were performed 20 and 60 minutes after injection of 1.5 MBq/kg of FCH. PET/CT acquisition was scored positive when maximal standardized uptake value in the IC nodule was higher than in the thyroid background. Pathology was the gold standard for diagnosis. Results: At pathology, 19 (18%) nodules were malignant, 87 were benign, and one was a noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Sensitivity, specificity, accuracy, positive-predictive value (PPV), and negative-predictive value (NPV) of FCH PET/CT in detecting cancer or NIFTP were 90%, 50%, 55%, 29%, and 96% at 20 minutes and 85%, 49%, 67%, 28%, and 94% at 60 minutes, respectively. Higher specificity (58% vs. 33%, p  = 0.01) was observed in nononcocytic ( n  = 72) than in oncocytic IC nodules ( n  = 35). The pre-PET/CT probability of cancer or NIFTP in Bethesda III-IV nodules was 11% and the post-PET/CT probability was 19% in PET-positives and 0% in PET-negatives. In retrospective analysis, 42% of surgeries would have been unnecessary after PET/CT and 81% before ( p  < 0.001), resulting in a hypothetical 48% reduction (95% confidence interval [32-64]). Conclusions: FCH PET/CT offers high NPV to reliably exclude cancer in PET-negative IC nodules, but suffers from low PPV, particularly in those with oncocytic cytology. ClinicalTrials.gov identifier: NCT02784223.

Objective: To discuss optimal treatment strategy for spindle cell oncocytoma (SCO) of the pituitary gland., Methods: Institutional cases were retrospectively reviewed. A systematic literature search and subsequent quantitative synthesis were performed for further analysis. The detailed features were summarized and the tumor control rate (TCR) was calculated., Results: Eighty-five patients (6 institutional and 79 literature) were included. The annual incidence was approximately 0.01-0.03/100,000. The mean age was 56 years. Vision loss was present in 60%. Seventy-three percent showed hormonal abnormalities. On magnetic resonance imaging, tumor was avidly enhancing, and the normal gland was commonly displaced anterosuperiorly. Evidence of hypervascularity was seen in 77%. Gross total resection (GTR) was achieved in only 24% because of its hypervascular, fibrous, and adhesive nature. The mean postoperative follow-up was 3.3 years for institutional cases and 2.3 years for the integrated cohort. The TCR was significantly better after GTR (5-year TCR, 75%; P = 0.012) and marginally better after non-GTR + upfront radiotherapy (5-year TCR, 76%; P = 0.103) than after non-GTR alone (5-year TCR, 24%). The TCRs for those with low Ki-67 index (≤5%) were marginally better than those with higher Ki-67 index (5-year rate, 57% vs. 23%; P = 0.110)., Conclusions: Frequent endocrine-related symptoms, hypervascular signs, and anterosuperior displacement of the gland support preoperative diagnosis of SCO. GTR seems to have better long-term tumor control, whereas the fibrous, hypervascular, and adhesive nature of SCO makes it difficult to achieve GTR. In patients with non-GTR, radiotherapy may help decrease tumor progression., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Oncocytoma is a rare benign neoplasm with few cases reported to involve the orbit. When affecting the orbit, oncocytomas have very slow growth and often evade early diagnosis. The diagnostic evaluation of these orbital tumors is not fully understood. The authors present a case of a benign oncocytoma arising in the lacrimal gland associated with significant vascularity and intraoperative bleeding. The authors provide immunohistochemical analysis of this rare orbital tumor and insights in surgical planning., Competing Interests: The authors have no financial or conflicts of interest to disclose., (Copyright © 2021 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

We presented an extremely rare entity of 'hybrid' oncocytoma and collecting duct (Bellini) carcinoma. The intratumoural coexistence of benign and malignant cells may lead to false diagnosis and suboptimal treatment of an aggressive tumour. Diagnosis may be challenging if only based on imaging modalities. Even the established value of targeted renal biopsy may be questioned in such scarce cases. Consequently, active surveillance for small renal tumours shall not considered a widely safe management., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)