MRI findings of sarcomatoid renal cell carcinoma in nine cases

Renal cell carcinoma and venous tumor thrombus: predicting sarcomatoid dedifferentiation through preoperative IVIM-based MR imaging

PURPOSE

To evaluate the value of preoperative intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and conventional MRI indicators in identifying sarcomatoid dedifferentiation in renal cell carcinoma (RCC) and tumor thrombus.

METHODS

From September 2016 to April 2023, consecutive patients with RCC and tumor thrombus who received routine MRI examination and IVIM-DWI before radical resection were enrolled prospectively. Kaplan-Meier method with log-rank test was used to calculate and compare the survival probability. The preoperative imaging features were analyzed. Univariate and multivariable logistic regression analyses were employed to identify independent predictors of sarcomatoid dedifferentiation. The predictive ability was evaluated by receiver operating characteristic (ROC) curves.

RESULTS

Twenty-two patients (15.3%) of the 144 patients in the training set (median age, 58.0 years [IQR, 52.0-65.0 years]; 108 men) and 11 patients (22.4%) of the 49 patients in the test set (median age, 58.0 years [IQR, 53.0-63.0 years]; 38 men) had sarcomatoid dedifferentiated tumors. Patients with sarcomatoid-differentiated tumors had poor progress-free survival in the training set and test set (P < 0.001 and P = 0.007). f value (P = 0.011), mN stage (P = 0.007), and necrosis (P = 0.041) were independent predictors for predicting sarcomatoid dedifferentiation in the training set. The model combining conventional MRI features and f value had AUCs of 0.832 (95% CI 0.755-0.909) and 0.825 (95% CI 0.702-0.948) in predicting sarcomatoid dedifferentiation in the training set and test set.

CONCLUSION

It is feasible to preoperatively identify sarcomatoid dedifferentiation based on IVIM-DWI and conventional MR imaging indicators.

Magnetic Resonance Imaging Virtual Biopsy of Common Solid Renal Masses-A Pictorial Review

ABSTRACT

The expanded application of radiologic imaging resulted in an increased incidence of renal masses in the recent decade. Clinically, it is difficult to determine the malignant potential of the renal masses, thus resulting in complex management. Image-guided biopsies are the ongoing standard of care to identify molecular variance but are limited by tumor accessibility and heterogeneity. With the evolving importance of individualized cancer therapies, radiomics has displayed promising results in the identification of tumoral mutation status on routine imaging. This article discusses how magnetic resonance imaging features can guide a radiologist toward identifying renal mass characteristics.

Sarcomatoid renal cell carcinoma: MRI features and their association with survival

OBJECTIVE

To evaluate MRI features of sarcomatoid renal cell carcinoma (RCC) and their association with survival.

METHODS

This retrospective single-center study included 59 patients with sarcomatoid RCC who underwent MRI before nephrectomy during July 2003-December 2019. Three radiologists reviewed MRI findings of tumor size, non-enhancing areas, lymphadenopathy, and volume (and percentage) of T2 low signal intensity areas (T2LIA). Clinicopathological factors of age, gender, ethnicity, baseline metastatic status, pathological details (subtype and extent of sarcomatoid differentiation), treatment type, and follow-up were extracted. Survival was estimated using Kaplan-Meier method and Cox proportional-hazards regression model was used to identify factors associated with survival.

RESULTS

Forty-one males and eighteen females (median age 62 years; interquartile range 51-68) were included. T2LIAs were present in 43 (72.9%) patients. At univariate analysis, clinicopathological factors associated with shorter survival were: greater tumor size (> 10 cm; HR [hazard ratio] = 2.44, 95% CI 1.15-5.21; p = 0.02), metastatic lymph nodes (present; HR = 2.10, 95% CI 1.01-4.37; p = 0.04), extent of sarcomatoid differentiation (non-focal; HR = 3.30, 95% CI 1.55-7.01; p < 0.01), subtypes other than clear cell, papillary, or chromophobe (HR = 3.25, 95% CI 1.28-8.20; p = 0.01), and metastasis at baseline (HR = 5.04, 95% CI 2.40-10.59; p < 0.01). MRI features associated with shorter survival were: lymphadenopathy (HR = 2.24, 95% CI 1.16-4.71; p = 0.01) and volume of T2LIA (> 3.2 mL, HR = 4.22, 95% CI 1.92-9.29); p < 0.01). At multivariate analysis, metastatic disease (HR = 6.89, 95% CI 2.79-16.97; p < 0.01), other subtypes (HR = 9.50, 95% CI 2.81-32.13; p < 0.01), and greater volume of T2LIA (HR = 2.51, 95% CI 1.04-6.05; p = 0.04) remained independently associated with worse survival.

CONCLUSION

T2LIAs were present in approximately two thirds of sarcomatoid RCCs. Volume of T2LIA along with clinicopathological factors were associated with survival.

Magnetic resonance imaging (MRI) helps differentiate renal cell carcinoma with sarcomatoid differentiation from renal cell carcinoma without sarcomatoid differentiation

PURPOSE

The aim of the present study is to identify predictive imaging findings and construct a diagnostic model for differentiating renal cell carcinoma (RCC) with and without sarcomatoid dedifferentiation (sRCC and non-sRCC).

METHODS

This study is a single-center retrospective study. All patients had magnetic resonance imaging (MRI) with gradient-echo T1-weighted images, single-shot T2-weighted images (T2WI), and enhanced nephrographic phase images. Forty pathologically confirmed sRCCs and 80 non-sRCCs were included in this study. Control cases were selected by matching the tumor diameter and the year of MRI. Two radiologists independently evaluated the following findings: growth pattern, presence of low-intensity area on T2WI in the tumor (T2LIA), presence of non-enhancing area, local tumor stage, and presence of regional lymphadenopathy. Two radiologists measured the diameter of the tumor, T2LIA, and the non-enhancing area. Multivariable logistic regression analysis was used to identify independent predictive factors for differentiating sRCC from non-sRCC. Selected variables were entered in the logistic regression model, and the area under the curve (AUC) was calculated for each reader with 95% confidence intervals (CIs).

RESULTS

Larger T2LIA-to-tumor diameter ratio, regional lymphadenopathy, and local tumor stage 4 were associated with sRCC, and selected for the subsequent construction of a logistic regression model. With this model, the AUCs were 0.76 (95% CI, 0.66-0.85) and 0.70 (95% CI, 0.59-0.81) for prediction of sRCC.

CONCLUSION

In conclusion, larger T2LIA-to-tumor diameter ratio, regional lymphadenopathy, and local tumor stage 4 are predictive findings of sRCC. As a result, the model constructed using these findings demonstrated a moderate degree of diagnostic accuracy.

Sarcomatoid renal cell carcinoma: biology, natural history and management

Sarcomatoid dedifferentiation is an uncommon feature that can occur in most histological subtypes of renal cell carcinomas (RCCs) and carries a decidedly poor prognosis. Historically, conventional treatments for sarcomatoid RCCs (sRCCs) have shown little efficacy, and median survival is commonly 6–13 months. Despite being first described in 1968, the mechanisms driving sarcomatoid dedifferentiation remain poorly understood, and information and treatment options available to physicians and patients are limited. When diagnosed at an early stage, surgical intervention remains the treatment of choice. However, preoperative identification through routine imaging or biopsy is unreliable and most patients present with advanced disease and systemic symptoms. For these patients, the role of cytoreductive nephrectomy is disputed. The expansion of immunotherapies approved for RCCs has generated a search for biomarkers that might be indicative of treatment response in sRCCs, although a proven effective systemic agent remains elusive. PDL1 expression is increased in sarcomatoid dedifferentiated renal tumours, which suggests that patients with sRCCs could benefit from PD1 and/or PDL1 immune checkpoint blockade therapy. Treatment outcomes for sarcomatoid tumours have remained relatively consistent compared with other RCCs, but further investigation of the tumour–immune cell microenvironment might yield insights into further therapeutic possibilities.

In this Review, Blum et al. summarize the current knowledge on sarcomatoid renal cell carcinoma, a diagnosis characterized by the presence of sarcomatoid dedifferentiation and a poor prognosis. They discuss the origin, presentation, molecular biology and treatment of this disease.

Sarcomatoid dedifferentiation is not considered to be a unique histological subtype of renal cell carcinomas (RCCs); rather, it can be present within any subtype of RCCs.

Sarcomatoid dedifferentiation appears in ~4% of all RCCs, but is present in ~20% of all metastatic RCCs. According to WHO guidelines, any RCC with sarcomatoid dedifferentiation is a WHO–International Society of Urological Pathology grade 4 lesion.

Sarcomatoid dedifferentiation is often heterogeneously present within RCCs, making routine imaging and biopsy unreliable for preoperative detection. Surgical resection for localized disease is the standard of care, with subsequent close monitoring of patients following surgery.

In patients with metastatic disease, conventional therapies such as surgery and systemic agents have been ineffective and overall 5-year survival remains at 23.5–33%.

Previous genomic analyses have failed to identify definitive mutational drivers of disease. However, sarcomatoid RCCs (sRCCs) have been shown to have higher PD1 and PDL1 expression than other subtypes of RCCs. Newer combinations of immune checkpoint inhibitor immunotherapies could yield improved responses and outcomes.

Studies investigating sRCCs are limited by patient numbers owing to the low incidence of sRCCs and their advanced stage at presentation. Multi-institutional efforts to establish a consensus on treatment recommendations based on highly powered data are essential.

FDG PET/CT and CT Findings of Renal Cell Carcinoma With Sarcomatoid Differentiation

OBJECTIVE. The purpose of this article is to investigate the value of ¹⁸F-FDG PET/CT and enhanced CT in the diagnosis of renal cell carcinoma (RCC) with sarcomatoid differentiation and the differential diagnosis of clear cell renal cell carcinoma (ccRCC). MATERIALS AND METHODS. Among patients with renal tumors confirmed by pathologic examination from September 2010 to August 2019, 29 patients with RCC with sarcomatoid differentiation and 82 patients with ccRCC who underwent FDG PET/CT, renal contrast-enhanced CT examination, or both, before surgery were studied. Features of the two groups on CT and PET/CT were retrospectively reviewed. RESULTS. The tumor size of RCC with sarcomatoid differentiation was larger than that of ccRCC (p = 0.0086). Cystic necrosis, peritumoral neovascularity, and metastasis were more common in RCC with sarcomatoid differentiation (p = 0.0052, p = 0.0008, p < 0.0001, respectively). The ratio of necrotic area to tumor diameter of RCC with sarcomatoid differentiation was statistically significantly larger than that of ccRCC (p = 0.0032). Three cases of RCC with sarcomatoid differentiation showed a large central necrotic area and dense intratu-moral neovascularity in the surrounding parenchyma, defined as the ring-of-fire sign, which was not found in ccRCC. The maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean), and peak standardized uptake value (SUV_peak) of RCC with sarcomatoid differentiation were statistically significantly higher than those for ccRCC (all p < 0.0001), and the SUV_max, SUV_mean, and SUV_peak cutoff values of 5.4, 4.2, and 5.0, respectively, were helpful for discrimination. CONCLUSION. Imaging features including higher SUV_max, SUV_mean, and SUV_peak; a larger ratio of necrotic area to tumor diameter; the presence of peritumoral neovascularity; and metastasis are more commonly associated with RCC with sarcomatoid differentiation than with ccRCC. The ring-of-fire sign and SUV_max, SUV_mean, SUV_peak cutoff values of 5.4, 4.2, 5.0, respectively, may be helpful to indicate RCC with sarcomatoid differentiation.

Sarcomatoid renal cell carcinoma: a case report and literature review

BACKGROUND

The poorly differentiated renal cell carcinoma (RCC) with rhabdomyosarcomatous sarcomatoid differentiation shows a severely aggressive biological behavior characterized by rapid disease progression. Preoperative identification of the subtype with the prognostic factors and imaging features of sarcomatoid renal cell carcinoma (SRCC) would be of great clinical significance.

CASE PRESENTATION

A 45-year-old male patient presented a nine day history of gross hematuria without any other symptoms. A computed tomography (CT) and a full-body fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) - computed tomography (CT) scan urogram were performed. An initial diagnosis identified a space-occupying lesion of the right kidney, retroperitoneal and right renal hulum lymph node metastases, as well as a space-occupying lesion of the third thoracic vertebra (T3). A right radical nephrectomy was performed. Pathologic analysis revealed poorly differentiated RCC with rhabdomyosarcomatous sarcomatoid differentiation that extends into the renal sinus and the ureteral (T3N1M1). Five days later, the Magnetic Resonance imaging (MRI) evidenced a diffused osseous metastatic disease in the thoracic and lumbar vertebra and multiple retroperitoneal lymph node metastases. The disease progressed quickly to multiple organ dysfunction syndrome (MODS) in half a month and the patient died of respiratory failure two days later. The patient refused any chemoradiotherapy in the hospital.

CONCLUSIONS

Our case presents a SRCC with severe, aggressive, and rapid disease progression. Classifying SRCC imaging features by CT, MRI as well as PET-CT techniques could potentially be helpful for preoperative identification of the subtype. The prognostic factors of SRCC would be of great clinical interest.

Sarcomatoid Renal Cell Carcinoma and Collecting Duct Carcinoma: Discrimination From Common Renal Cell Carcinoma Subtypes and Benign RCC Mimics on Multiphasic MDCT

RATIONALE AND OBJECTIVES

To investigate whether imaging features on multiphasic multidetector computed tomography (MDCT) can help discriminate sarcomatoid renal cell carcinoma (RCC) and collecting duct carcinoma (CDC) from other solid renal masses.

MATERIALS AND METHODS

With institutional review board approval for this HIPAA-compliant study, we derived a cohort of 7 sarcomatoid RCCs, 4 CDCs, 165 clear cell RCCs, 56 papillary RCCs, 22 chromophobe RCCs, 49 oncocytomas, and 16 lipid-poor angiomyolipomas with preoperative multiphasic MDCT with up to four phases (unenhanced, corticomedullary, nephrographic, and excretory). Each lesion was reviewed for contour, spread pattern, pattern of enhancement, neovascularity, and calcification.

RESULTS

Sarcomatoid RCCs and CDCs were more likely than other solid renal masses to have an irregular contour (64% vs 2%, P < 0.001) and an infiltrative spread pattern, defined as infiltration into adjacent renal parenchyma, collecting system, or neighboring structures (82% vs 7%, P < 0.001). When used to discriminate sarcomatoid RCC and CDC from other solid renal masses, an infiltrative spread pattern had a specificity of 93% (287/308) and sensitivity of 82% (9/11), and an irregular contour had a specificity of 98% (303/308) and sensitivity of 64% (7/11).

CONCLUSIONS

Solid renal lesions with an irregular contour or an infiltrative spread pattern are suspicious for sarcomatoid RCC or CDC.

Sarcomatoid renal cell carcinoma: case report and review of literature

Sarcomatoid renal cell carcinoma is a tumour with aggressive behaviour. It is a form of dedifferentiated carcinoma with high incidence of metastases to the lungs. We report a case of 55-year-old male who presented with complaints of loin pain and hematuria. The biopsy confirmed sarcomatoid variant of renal cell carcinoma.

Clinicopathologic characteristics and prognostic factors of sarcomatoid renal cell carcinoma

OBJECTIVES

We seek to summarize the clinicopathologic characteristics and prognostic factors of sarcomatoid renal cell carcinoma (SRCC), an uncommon type of renal cell carcinoma.

METHODS AND MATERIALS

Between 2004 and 2012, 23 patients with SRCC were treated at a large urology center in south central China. We collect patient's clinicopathologic features from medical records to assess diagnosis, prognostic factors and efficacy of systemic therapy. Clinical data were absent in 3 cases, and 20 patients were enrolled in the final study.

RESULTS

Immunohistochemically, almost all SRCC expressed cytokeratin (91%), epithelial membrane antigen (87%) and vimentin (100%). Sarcomatoid differentiation occurs in various kinds of subtypes of RCC with almost the same probability. The median tumor size was 10.5 cm. The CT findings of these tumors revealed low-density (n = 5; 25%) or mixed (n = 15; 75%) masses with necrotic areas and often showed an infiltrative morphology (n = 15; 75%). All 20 cases demonstrated heterogeneous enhancement, and eleven (55%) cases demonstrated >50% necrosis. Six cases complicated with calculus and hydronephrosis. Sixteen (80%) patients demonstrated invasions of tissues localized in Gerota's fascia, and 8 (40%) tumors invaded beyond Gerota's fascia. Fifteen (75%) patients demonstrated lymph node metastasis, and sixteen (80%) patients had distant metastasis. Five patients received systemic therapy, and one patient given high-dose interferon-α had a completely response, and one patient received chemotherapy based on gemcitabine had partial response. The median overall survival of all patients was 5.8 months. Patients without distant metastasis had a median overall survival of 35 months compared with 3 months of those with distant metastasis (P < 0.002). The percentage of the sarcomatoid components did not have an obvious influence to the prognosis (P = 0.197).

CONCLUSIONS

Heterogeneity, hugeness, infiltration and necrosis are typical image features of SRCC. The prognosis of SRCC is poor and clinic stage especially the existence of distant disease is the important factor influencing prognosis.

MRI phenotype in renal cancer: is it clinically relevant?

Renal cell carcinoma (RCC) is most commonly diagnosed as an incidental finding on cross-sectional imaging and represents a significant clinical challenge. Although most patients have a surgically curable lesion at the time of diagnosis, the variability in the biologic behavior of the different histologic subtypes and tumor grade of RCC, together with the increasing array of management options, creates uncertainty for the optimal clinical approach to individual patients. State-of-the-art magnetic resonance imaging (MRI) provides a comprehensive assessment of renal lesions that includes multiple forms of tissue contrast as well as functional parameters, which in turn provides information that helps to address this dilemma. In this article, we review this evolving and increasingly comprehensive role of MRI in the detection, characterization, perioperative evaluation, and assessment of the treatment response of renal neoplasms. We emphasize the ability of the imaging "phenotype" of renal masses on MRI to help predict the histologic subtype, grade, and clinical behavior of RCC.

[A case of renal spindle cell carcinoma]

An asymptomatic 67-year-old woman was found to have renal tumors by chance on a screening abdominal ultrasound examination. Although surgical resection was planned for both a diagnostic purposes and treatment, she suddenly developed hemorrhage from the cerebral metastasis in the left thalamus, and the surgical procedure was postponed. Irradiation with a gamma knife was performed to treat the cerebral metastasis; however, the patient's general condition quickly worsened, and she died six months after diagnosis. An autopsy showed typical spindle cells in the primary lesion with multiple metastases. Renal spindle cell carcinoma is a relatively rare type of the renal carcinoma that is both very aggressive and exhibits a poor prognosis, with few established treatments. Hence, obtaining an early diagnosis on abdominal ultrasound is important in such cases.

Characteristic MRI findings of sarcomatoid renal cell carcinoma dedifferentiated from clear cell renal carcinoma: radiological-pathological correlation

PURPOSE

To evaluate MRI findings of sarcomatoid renal cell carcinoma (SRCC).

MATERIAL AND METHODS

Eleven patients with pathologically proven SRCC dedifferentiated from clear cell renal carcinoma (CCRC) underwent preoperative renal MRI. The MRI findings were compared with histological findings. On MRI, the following findings were evaluated: the presence and distribution of areas showing heterogeneous iso to high signal intensity (SI) on T2-weighted images (T2HIA) and conspicuously low SI areas (T2LIA) compared to normal renal cortex, areas showing high SI on T1-weighted images and unenhanced areas on dynamic contrast-enhanced images, disruption of pseudocapsule, and the SIs of T2HIA and T2LIA on diffusion-weighted imaging (DWI). The apparent diffusion coefficient (ADC) values and SI ratios to muscle on dynamic contrast-enhanced imaging (DCE) were compared between T2HIA and T2LIA using the t test.

RESULTS

The distribution of T2HIA and T2LIA was as follows: a mixed pattern alone in five, nodular T2LIA pattern alone in one, both mixed and nodular T2LIA patterns in four, and a separated pattern in one. Disruption of the pseudocapsule was seen in all cases. The imaging findings suggesting intratumoral hemorrhage and necrosis were seen in 18% and 63%, respectively. The SIs of T2HIA and T2LIA were low intermediate and high on DWI, respectively. T2LIA and T2HIA corresponded to the components of SRCC with abundant fibrosis and CCRC, respectively. T2LIA showed significantly lower enhancement at all DCE phases and a lower ADC value than T2HIA.

CONCLUSION

The presence of T2LIA corresponding to the area showing a hypovascular nature and markedly restricted diffusion might be characteristic findings of SRCC. Intratumoral hemorrhage and necrosis were seen, but they were not specific findings.

[Sarcomatoid renal cell carcinoma]

INTRODUCTION

The objective was to perform a systematic review of literature concerning epidemiology, clinical and biological data, prognosis and therapy of sarcomatoid renal cell carcinomas.

MATERIAL AND METHODS

Data on sarcomatoid renal cell carcinomas have been sought by querying the server Medline with MeSH terms following or combination of them: "renal carcinoma", "renal cell carcinoma," "renal cancer", "sarcomatoid" "sarcomatoid transformation" and "sarcomatoid differentiation." The articles obtained were selected according to their methodology, the language in English or French, the relevance and the date of publication. Twenty papers were selected.

RESULTS

According to the literature, a sarcomatoid contingent can be observed in all subtypes of renal cell carcinomas, with a frequency of 1 to 15% of cases. The median age at diagnosis was 60 years with a majority of symptomatic patients (90%), mainly with abdominal pain and hematuria. These tumors were often found in patients with locally advanced or metastatic (45-77%). The imaging was not specific for the diagnosis and biopsy had a low sensitivity for identifying a sarcomatoid contingent. The treatment was based on a combination of maximal surgical resection whenever possible and systemic therapy for metastastic disease. Pathological data often showed large tumors, Furhman 4 grades, combined biphasic carcinomatous contingent (clear cell carcinoma in most cases) and sarcomatoid. Genetically, there was no specific abnormality but a complex association of chromosomal additions and deletions. The prognosis was pejorative with a specific median survival of 5 to 19 months without any impact of the sarcomatoid contingent rate.

CONCLUSION

Sarcomatoid renal cell carcinoma is a form not to ignore despite its rarity. Mainly symptomatic and discovered at an advanced stage, it has a poor prognosis, requiring multidisciplinary management quickly and correctly.

Sarcomatoid renal cell carcinoma: a case report and literature review

Renal cell carcinoma (RCC) is the most common malignancy of the kidney and consists of multiple subtypes. The sarcomatoid variety, while previously considered a distinct histologic subtype, is now categorized as a form of dedifferentiated carcinoma. When present, it is associated with a significant decrease in patient survival due to its rapid growth and intrusive behavior. Preoperative knowledge of this diagnosis may be beneficial to clinicians in order to modify treatment options and follow-up protocols. This report describes a case of sarcomatoid renal cell carcinoma in which the patient initially presented with flank pain. We then discuss the clinical features of sarcomatoid renal cell carcinoma and its imaging appearance on computed tomography (CT), and succinctly review the subtypes of renal cell carcinoma and their imaging characteristics.