Search Results (64)

Introduction: Low-grade oncocytic tumor (LOT) is a recently described renal neoplasm characterized by indolent clinical behavior, a small nested architecture, and distinctive immunophenotypic features. Its distinction from other eosinophilic renal tumors, such as oncocytoma, eosinophilic chromophobe renal cell carcinoma (E-chRCC), and eosinophilic vacuolated tumor (EVT), can be challenging due to overlapping features. The L1 cell adhesion molecule (L1CAM) is being increasingly recognized as a potential diagnostic marker for LOT. Aims: To evaluate the diagnostic performance of L1CAM in distinguishing LOT from morphologically and immunophenotypically similar eosinophilic renal neoplasms. Methods: A total of 54 eosinophilic renal tumors (10 LOTs, 22 oncocytomas, 18 E-chRCCs, and 4 EVTs) were retrospectively collected from five academic institutions and reclassified according to the 2022 WHO criteria. All cases underwent histopathologic review and immunohistochemical analysis for CK7, CD117, GATA3, cathepsin K, and L1CAM. Results: L1CAM showed strong membranous expression in all LOTs (100%) and was negative in oncocytoma, E-chRCC, and EVT, yielding 100% sensitivity and specificity. Traditional markers exhibited overlapping patterns among tumor types. Conclusions: Our findings confirm L1CAM as a highly sensitive and specific marker for LOT, effectively distinguishing it from other eosinophilic renal neoplasms. Incorporating L1CAM into diagnostic panels may enhance accuracy, particularly in challenging cases. Full article

Background: Oncocytoma and angiomyolipoma (AML) are benign renal tumors that may mimic malignant lesions on imaging. With the increasing use of partial nephrectomy (PN) for renal masses, accurate preoperative characterization of these lesions is essential. This study highlights the role of partial nephrectomy as a valuable diagnostic tool in situations where imaging is inconclusive or raises concern for malignancy without definitive confirmation. In the absence of a reliable preoperative diagnosis, partial nephrectomy provides direct histologic verification with minimal perioperative morbidity. Moreover, it offers curative potential when malignancy is present. By achieving both diagnostic certainty and renal preservation, this approach is well-suited for clinical scenarios in which imaging ambiguity might otherwise result in overtreatment through radical surgery or undertreatment Material and methods: in this retrospective study, we reviewed our 5-year experience (2019–2024), 188 partial nephrectomies—including bilateral procedures and operations on solitary kidneys—using robotic and open approaches. All of these 30 tumors were solid renal masses with indeterminate imaging features or suspicious characteristics suggestive of malignancy, further underscoring the limitations of current preoperative diagnostic modalities. Results: Histopathological evaluation confirmed benign renal tumors in 30 cases, with oncocytoma diagnosed in 18 cases (16 robotic, 2 open) and AML in 12 cases (9 robotic, 3 open). Conclusions: Even when imaging raises suspicion of malignancy or remains inconclusive, many small renal masses are ultimately confirmed as benign upon histopathological examination. This study underscores the diagnostic uncertainty associated with small renal tumors and highlights the value of partial nephrectomy as a decisive diagnostic intervention. In situations where non-invasive modalities fail to provide definitive answers, partial nephrectomy offers tissue confirmation with minimal morbidity. Furthermore, when malignancy is present, this approach ensures appropriate oncologic management while preserving renal function. Our findings support the integration of this strategy into routine clinical practice, particularly when diagnostic clarity is essential for guiding safe and effective treatment. Full article

Posterior pituitary tumors (PPTs) are rare, non-neuroendocrine neoplasms derived from pituicytes of the neurohypophysis or infundibulum. According to the 2025 WHO classification, PPTs comprise four distinct but related low-grade entities: pituicytoma, granular cell tumor of the sellar region, spindle cell oncocytoma, and ependymal pituicytoma. All share nuclear TTF-1 expression, confirming their common origin, but differ in morphology, immunophenotype, and ultrastructure. Histologically, pituicytomas consist of bipolar spindle cells in fascicles; granular cell tumors show polygonal cells with PAS-positive, diastase-resistant cytoplasmic granules; spindle cell oncocytomas display oncocytic change and abundant mitochondria; and ependymal pituicytomas exhibit perivascular pseudorosettes and EMA positivity in apical or dot-like patterns. Immunohistochemically, all are S100 and vimentin positive, and negative for pituitary hormones and lineage-specific transcription factors. Clinically, PPTs are typically non-functioning but may be associated with corticotroph or somatotroph hyperfunction. Imaging features are nonspecific. Surgical resection is the treatment of choice, although hypervascularity and adherence—especially in spindle cell oncocytomas—can hinder complete excision. Radiotherapy is reserved for recurrences. Molecular analyses reveal recurrent alterations in MAPK/PI3K pathways (e.g., HRAS, BRAF, FGFR1, NF1, TSC1) and suggest a shared histogenesis. Copy number imbalances correlate with reduced progression-free survival in some subtypes. Despite a generally favorable prognosis, recurrence—particularly in spindle cell oncocytomas—necessitates long-term follow-up. The WHO 2025 update provides a unified framework for classification, diagnosis, and prognostic stratification of these rare tumors. Full article

Background: Differentiating histologic subtypes of fat-poor small renal masses using conventional imaging remains difficult due to their overlapping radiologic characteristics. We aimed to develop a machine learning-based diagnostic model using CT-derived radiomic features to classify the five most common renal tumor subtypes: clear cell RCC (ccRCC), papillary RCC (pRCC), chromophobe RCC (chRCC), angiomyolipoma (AML), and oncocytoma. Methods: A total of 499 patients with pathologically confirmed renal tumors who underwent preoperative contrast-enhanced CT and nephrectomy were retrospectively analyzed. Results: We extracted and analyzed radiomic features from 1548 multi-phase CT scans from 499 patients, focusing on fat-poor tumors. Five machine learning classifiers including Linear SVM, Rbf SVM, Random Forest, and XGBoost were involved. Among the models, XGBoost showed the best classification performance, with an average AU-PRC: mean = 0.757, standard error = 0.033 and a renal angiomyolipoma-specific AU-ROC: mean = 0.824, standard error = 0.023. These results outperformed other single-phase CT radiomic feature-based machine learning models trained with 20% of principal components. Conclusions: This study demonstrates the effectiveness of radiomics-based machine learning in classifying renal tumor subtypes and highlights the potential of AI in medical imaging. The findings, particularly the utility of single-phase CT and feature optimization, offer valuable insights for future precision medicine approaches. Such methods may support more personalized diagnosis and treatment planning in renal oncology. Full article

Renal cell carcinoma (RCC) is a major global health issue with an increasing incidence and mortality rate. Current diagnostic methods are either invasive or limited in their ability to accurately differentiate between benign and malignant tumours and to predict early treatment response. This can lead to incorrect diagnosis, delayed treatment, patient anxiety, and suboptimal outcomes. RCC subtypes are known to exhibit distinct metabolic alterations, for example in glucose metabolism. These metabolic phenotypes offer potential targets for non-invasive imaging techniques to improve diagnosis and treatment, but current clinically available metabolic imaging tools such as ¹⁸F-FDG-PET and ^99mTc-sestamibi SPECT have limitations. Therefore, new approaches are required to assess this metabolism, and novel metabolic MRI techniques including hyperpolarised [1-¹³C]pyruvate MRI and deuterium metabolic imaging offer promising alternatives. These techniques are non-radioactive, demonstrate spatial metabolic heterogeneity, and can probe metabolic flux beyond tracer uptake. This review aims to explore the potential of metabolic MRI in the clinical management of RCC by (1) summarising current clinical guidelines; (2) reviewing metabolic heterogeneity across RCC subtypes; (3) discussing the potential of metabolic MRI to advance the understanding of in vivo metabolism; (4) and finally suggesting future directions for research in this field. Full article

Introduction: The group of so-called “sellar-region masses” consists of a heterogeneous group of neoplasms and tumor-mimicking lesions, whose differential diagnosis may be challenging due to the overlapping of clinical and radiological features, which can be found both in “common” and “uncommon” lesions. The choice of a correct treatment strategy is still arduous and requires histological analysis. Gamma Knife Radiosurgery (GKRS) has already been reported as a safe and effective treatment in these cases. The objective of this study is to evaluate single-center pre-operative data, post-operative outcomes, and long-term follow-up in patients treated with GKRS for unusual sellar tumors. Methods: We retrospectively identified and analyzed nine patients treated with GKRS from 2004 to 2015, according to a standard protocol. Lesions consist of hypothalamic hamartoma (HH), Rathke’s cleft cist (RCC), Langerhans cell histiocytosis (LCH), spindle cell oncocytoma (SCO), choroid plexus papilloma (CPP), and ossifying fibroma (OF). The diagnosis was histologically confirmed in six patients that underwent surgery, while in three patients, diagnosis was based on characteristic clinical and radiological findings (two HH and one RCC). Pre-operative and post-operative data were retrieved from medical archives, and long-term follow-up was obtained through clinical and neuroradiological periodic examination. Results: In our series, all the “rare” sellar lesions treated, had a successful radiographic and clinical response in a medium-long follow-up period. Conclusions: The long-term follow-up results suggest that GKRS is a safe and effective treatment in rare sellar lesions, with very low toxicity. To the best of our knowledge, this report represents the largest series of unusual sellar lesions treated with GKRS in a single high-volume center, suggesting that GKRS might be an effective non-invasive adjuvant treatment option. Further studies and a larger number of patients are needed to confirm if residuals of these rare sellar lesions might regress on their own without treatment or if other non-invasive treatments could be as effective as GKRS. Full article

Kidney and renal pelvic cancer are a significant cause of cancer-related deaths, with the most common malignant kidney tumor being renal cell carcinoma (RCC). Chromophobe renal cell carcinoma is a rarer form of RCC that poses significant challenges to accurate diagnosis, as it shares many histologic features with Oncocytoma, a benign renal tumor. Biopsies for histopathological and immunohistochemical analysis have limitations in distinguishing chromophobe RCC from Oncocytoma. Syndromic cases may also have tumors with overlapping features. Techniques such as infrared (IR) spectroscopic imaging have shown promise as an alternative approach to tissue diagnostics. In this study, we propose a deep-learning-based framework for automating classification in kidney tumor tissue microarrays (TMAs) using an IR dataset. Feature selection algorithms reduce data dimensionality, followed by a deep learning classification approach. A classification accuracy of 91.3% was observed for validation data, even with the use of 13.6% of all wavelengths, thereby reducing training time by 21% compared to using the entire spectrum. Through the integration of scalable deep learning models coupled with feature selection, we have developed a classification pipeline with high predictive power, which could be integrated into a high-throughput real-time IR imaging system. This would create an advanced diagnostic tool for the detection and classification of renal tumors, namely chromophobe RCC and Oncocytoma. This may impact patient outcomes and treatment strategies. Full article

Background/Objectives: Spindle cell oncocytomas (SCOs) of the pituitary gland are rare tumors often misdiagnosed for nonfunctioning pituitary macroadenomas. Although classified as grade 1, they are often challenging in terms of diagnosis and treatment. Pituitary SCOs harbor peculiar features such as hypervascularity and stronger adherence to surrounding structures, with increased risk of hemorrhage, partial resection, and significantly higher recurrence rate. Almost 100 cases have been reported so far. The role of surgery is still crucial for the decompression of the optic chiasm as well as for achieving diagnosis. However, given the higher tendency of recurrence, the role of postoperative radiotherapy has been investigated over the last few years. Case presentation: Here, we reported a case of a 48-year-old female with a pituitary SCO treated at our institution, in which we focused on diagnosis, treatment, and follow-up. Conclusions: This type of tumor presents a challenge related to its higher vascularity and strong adherence to the surrounding structures. Adjuvant radiotherapy is something that should be considered, especially when gross total resection is not achieved, and finally, SCOs require diligent follow-up to monitor for any signs of disease recurrence or progression. Full article

Background/Objectives: Renal cell carcinoma is an aggressive form of kidney cancer, contributing to an estimated 138,000 deaths globally in 2017. Traditional treatments like chemotherapy and radiation are generally considered ineffective. Additionally, CD47 has been identified as a crucial tumor antigen involved in the development and progression of various cancers, including renal cell carcinoma. The interaction of CD47 with SIRPα triggers a “don’t eat me” signal to the macrophages, inhibiting phagocytosis. Much progress has been made in targeting CD47 for cancer immunotherapy in solid tumors (STs) and hematological malignancies. This study aimed to evaluate CD47 expression in malignant and benign renal cell tumors and compare it with prognostic histopathological parameters. Methods: We included 160 malignant and 26 benign tumors. The malignant tumors consisted of renal cell carcinoma (RCC) subtypes including 37 clear cell, 30 chromophobe, 30 papillary type 1, 29 papillary type 2, and 34 unclassified RCC cases. As for the benign tumors, we included 26 oncocytoma cases. All samples were stained with anti-CD47 antibodies by immunohistochemistry methods. Results: The statistical analysis yielded a significant correlation between CD47 expression and survival, metastasis, and capsule invasion for the unclassified RCC cases. We did not find any further significant correlation between CD47 expression and the studied parameters. Conclusions: To the best of our knowledge, our study is the first to research CD47 expression in benign and malignant renal carcinoma subtypes. Further large-scale studies are needed to determine the expression profile of CD47 in renal cell tumors. Full article

RO and ChRCC are kidney tumours with overlapping characteristics, making differentiation between them challenging. The objective of this research is to create a radiogenomics map by correlating radiomic features to molecular phenotypes in ChRCC and RO, using resection as the gold standard. Fourteen patients (6 RO and 8 ChRCC) were included in the prospective study. A total of 1,875 radiomic features were extracted from CT scans, alongside 632 cytobands containing 16,303 genes from the genomic data. Feature selection algorithms applied to the radiomic features resulted in 13 key features. From the genomic data, 24 cytobands highly correlated with histology were selected and cross-correlated with the radiomic features. The analysis identified four radiomic features that were strongly associated with seven genomic features. These findings demonstrate the potential of integrating radiomic and genomic data to enhance the differential diagnosis of RO and ChRCC, paving the way for more precise and non-invasive diagnostic tools in clinical practice. Full article

Background: Circulating tumor cells (CTCs) may be the missing renal cell carcinoma (RCC) biomarker. No-touch (NT) resection has shown benefit in several tumors. Methods: A randomized controlled trial comparing CTC and circulating mesenchymal cell (CMC) release in no-touch (NT) vs. conventional (C) laparoscopic RN. Blood samples were collected at operation room arrival (S0), specimen extraction (S1), postoperative D1, and D30. CTCs were isolated and analyzed using RUBYchip™. Results: Thirty-four patients were included. No significant differences were found between groups in CTC and CMC counts, count variations between time points, complications, and survival. The total circulating cell detection rates in the NT, C, and overall RCC groups were 58.3%, 80.0%, and 70.4% at S0; 41.6%, 86.7%, and 66.7% at S1; 50.0%, 64.3%, and 60.0% at D1; and 54.5%, 42.9%, and 44.0% at D30, respectively. A progressive decrease in CMCs was observed in the C group after surgery, especially at D1 (4.78 to 1.64 CMCs/7.5 mL blood, p = 0.035). Healthy controls had no circulating cells; however, high CMC counts were found in chronic inflammation controls and oncocytoma patients, with no significant difference from RCC patients (p = 0.460). Conclusions: NT RN did not reduce circulating cell release nor improve survival compared to C RN. Full article

Objectives: To determine the rate of benign pathology in cT1 tumors following partial nephrectomy in the Netherlands, thereby evaluating the rate of overtreatment. Methods: Data were collected from a nationwide database containing histopathology of resected renal tissue from 2014 to 2022. Patients who underwent partial nephrectomy for suspected RCC staged T1a-b were extracted for analysis. Data are shown in percentages, and multivariable logistic regression was performed to determine predictive factors for benign pathology. Results: 3409 cases were analyzed, of which 403 (12%) were benign and 3006 (88%) malignant. Subtype analysis showed 2126 (62%) cases of clear-cell RCC, followed by 604 (18%) of papillary RCC and 344 (10%) oncocytomas. Mean age was 63 years among patients with malignant pathology versus 65 years for patients with benign lesions (p < 0.001). Mean tumor size was 3.2 cm for malignant pathology and 2.9 cm for benign (p < 0.001). The rates of benign and malignant pathology did not change between 2014 and 2022 (p = 0.377). Multivariable regression showed age ≥ 65 years (65–79 years [OR 1.881, p = 0.002], ≥ 80 years [OR 3.642, p < 0.001]) and tumor size (OR 0.793, p < 0.001) as predictors for benign pathology. The main limitation of this study is that we do not know the biopsy rate of our cohort. Conclusion: This study reports a low rate of 12% benign pathology after partial nephrectomy in the Netherlands. It remains debatable whether these rates are acceptable, or if renal tumor biopsies should be utilized more frequently to reduce overtreatment. Full article

Introduction: Imaging in renal cell carcinoma (RCC) is a constantly evolving landscape. The incidence of RCC has been rising over the years with the improvement in image quality and sensitivity in imaging modalities resulting in “incidentalomas” being detected. We aim to explore the latest advances in imaging for RCC. Methods: A literature search was conducted using Medline and Google Scholar, up to May 2024. For each subsection of the manuscript, a separate search was performed using a combination of the following key terms “renal cell carcinoma”, “renal mass”, “ultrasound”, “computed tomography”, “magnetic resonance imaging”, “18F-Fluorodeoxyglucose PET/CT”, “prostate-specific membrane antigen PET/CT”, “technetium-99m sestamibi SPECT/CT”, “carbonic anhydrase IX”, “girentuximab”, and “radiomics”. Studies that were not in English were excluded. The reference lists of selected manuscripts were checked manually for eligible articles. Results: The main imaging modalities for RCC currently are ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). Contrast-enhanced US (CEUS) has emerged as an alternative to CT or MRI for the characterisation of renal masses. Furthermore, there has been significant research in molecular imaging in recent years, including FDG PET, PSMA PET/CT, ^99mTc-Sestamibi, and anti-carbonic anhydrase IX monoclonal antibodies/peptides. Radiomics and the use of AI in radiology is a growing area of interest. Conclusions: There will be significant change in the field of imaging in RCC as molecular imaging becomes increasingly popular, which reflects a shift in management to a more conservative approach, especially for small renal masses (SRMs). There is the hope that the improvement in imaging will result in less unnecessary invasive surgeries or biopsies being performed for benign or indolent renal lesions. Full article

The availability of imaging methods has enabled increased detection of kidney lesions, which are a common clinical problem. It is estimated that more than half of patients over the age of 50 have at least one undetermined mass in the kidney. The appropriate characterization and diagnosis of lesions imaged in the kidney allows for proper therapeutic management. Previously, contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) have been used in their extended diagnosis. However, the limitations of these techniques, such as radiation exposure, renal toxicity, and allergies to contrast agents, must be considered. Contrast-enhanced ultrasound (CEUS) is increasingly being used as an examination to resolve interpretive doubts that arise with other diagnostic methods. Indeed, it can be considered both as a problem-solving technique for diagnosing and distinguishing lesions and as a technique used for observation in preservative treatment. Evaluation of the enhancement curve over time on CEUS examination can help to differentiate malignant renal cell carcinoma (RCC) subtypes that should be resected from benign lesions, such as oncocytoma or angiomyolipoma (AML), in which surgery can be avoided. It allows for distinguishing between benign and malignant tumors, renal and pseudotumors, and solid and cystic tumors. Therefore, with recent advances in ultrasound technology, CEUS has emerged as a fast, reliable, and cost-effective imaging tool in the preoperative evaluation and diagnosis of solid renal masses. Full article

Introduction: Image-guided renal mass biopsy is gaining increased diagnostic acceptance, but there are limited data concerning the safety and diagnostic yield of biopsy for small renal masses (≤4 cm). This study evaluated the safety, diagnostic yield, and management after image-guided percutaneous biopsy for small renal masses. Methods: A retrospective IRB-approved study was conducted on patients who underwent renal mass biopsy for histopathologic diagnosis at a single center from 2015 to 2021. Patients with a prior history of malignancy or a renal mass >4 cm were excluded. Descriptive statistics were used to summarize patient demographics, tumor size, the imaging modality used for biopsy, procedure details, complications, pathological diagnosis, and post-biopsy management. A biopsy was considered successful when the specimen was sufficient for diagnosis without need for a repeat biopsy. Complications were graded according to the SIR classification of adverse events. A chi-squared test (significance level set at p ≤ 0.05) was used to compare the success rate of biopsies in different lesion size groups. Results: A total of 167 patients met the inclusion criteria. The median age was 65 years (range: 26–87) and 51% were male. The median renal mass size was 2.6 cm (range: one–four). Ultrasound was solely employed in 60% of procedures, CT in 33%, a combination of US/CT in 6%, and MRI in one case. With on-site cytopathology, the median number of specimens obtained per procedure was four (range: one–nine). The overall complication rate was 5%. Grade A complications were seen in 4% (n = 7), consisting of perinephric hematoma (n = 6) and retroperitoneal hematoma (n = 1). There was one grade B complication (0.5%; pain) and one grade D complication (0.5%; pyelonephritis). There was no patient mortality within 30 days post-biopsy. Biopsy was successful in 88% of cases. A sub-group analysis showed a success rate of 85% in tumors <3 cm and 93% in tumors ≥3 cm (p = 0.01). Pathological diagnoses included renal cell carcinoma (65%), oncocytoma (18%), clear cell papillary renal cell tumors (9%), angiomyolipoma (4%), xanthogranulomatous pyelonephritis (1%), lymphoma (1%), high-grade papillary urothelial carcinoma (1%), and metanephric adenoma (1%), revealing benign diagnosis in 30% of cases. The most common treatment was surgery (40%), followed by percutaneous cryoablation (22%). In total, 37% of patients were managed conservatively, and one patient received chemotherapy. Conclusion: This study demonstrates the safety and diagnostic efficacy of image-guided biopsy of small renal masses. The diagnostic yield was significantly higher for masses 3–4 cm in size compared to those <3 cm. The biopsy results showed a high percentage of benign diagnoses and informed treatment decisions in most patients. Full article