Renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion: Radiological findings mimicking papillary subtype

A Rare Case of Collecting Duct Carcinoma: A Comprehensive Analysis Using Ultrasound, Computed Tomography, and Histopathological Examination

Collecting duct renal cell carcinoma (cdRCC) is an exceptionally rare and aggressive subtype of renal cell carcinoma, accounting for approximately 1% of all renal tumors. This case is notable due to the comprehensive use of multi-modality imaging and detailed histopathological examination, offering valuable insights into the diagnostic challenges and management of this rare condition. A 64-year-old male presented with progressive right flank pain, hematuria, and decreased urine output. Imaging studies revealed a hypoechoic lesion in the right kidney, predominantly located in the hilar and perihilar regions, suggestive of a malignant renal tumor. Further diagnostic evaluation, including a right radical nephrectomy, was performed. The histopathological examination of the resected tissue confirmed the diagnosis of cdRCC, characterized by a tubulopapillary growth pattern, significant pleomorphism, and sarcomatoid changes. Immunohistochemical analysis showed strong positivity for epithelial membrane antigen and CK7, confirming the aggressive nature of the tumor. This case underscores the importance of early diagnosis and a comprehensive diagnostic approach to managing cdRCC. Despite advances in imaging techniques, a definitive diagnosis often relies on histopathological and immunohistochemical analysis. The aggressive nature of cdRCC and its generally poor prognosis highlight the need for prompt and accurate diagnosis to potentially improve patient outcomes. This report adds to the limited literature on cdRCC, emphasizing the challenges and considerations in diagnosing and managing this rare form of renal carcinoma.

MRI Characteristics of Pediatric and Young-Adult Renal Cell Carcinoma: A Single-Center Retrospective Study and Literature Review

Pediatric renal cell carcinoma (RCC) is a rare malignancy. Magnetic resonance imaging (MRI) is the preferred imaging modality for assessment of these tumors. The previous literature has suggested that cross-sectional-imaging findings differ between RCC and other pediatric renal tumors and between RCC subtypes. However, studies focusing on MRI characteristics are limited. Therefore, this study aims to identify MRI characteristics of pediatric and young-adult RCC, through a single-center case series and literature review. Six identified diagnostic MRI scans were retrospectively assessed, and an extensive literature review was conducted. The included patients had a median age of 12 years (63-193 months). Among other subtypes, 2/6 (33%) were translocation-type RCC (MiT-RCC) and 2/6 (33%) were clear-cell RCC. Median tumor volume was 393 cm³ (29-2191 cm³). Five tumors had a hypo-intense appearance on T2-weighted imaging, whereas 4/6 were iso-intense on T1-weighted imaging. Four/six tumors showed well-defined margins. The median apparent diffusion coefficient (ADC) values ranged from 0.70 to 1.20 × 10^-3 mm²/s. In thirteen identified articles focusing on MRI characteristics of MiT-RCC, the majority of the patients also showed T2-weighted hypo-intensity. T1-weighted hyper-intensity, irregular growth pattern and limited diffusion-restriction were also often described. Discrimination of RCC subtypes and differentiation from other pediatric renal tumors based on MRI remains difficult. Nevertheless, T2-weighted hypo-intensity of the tumor seems a potential distinctive characteristic.

Beyond Wilms tumor: imaging findings and outcomes of rare renal tumors in children

BACKGROUND

Compared to Wilms, non-Wilms renal tumors in children are less well understood due to their rare occurrence which limits precise definition of the typical imaging patterns.

OBJECTIVE

This study aims to identify distinctive imaging findings, demographic characteristics and prognosis of pediatric non-Wilms renal tumors.

MATERIALS AND METHODS

From January 2007 to December 2018, 207 patients with a diagnosis of primary kidney neoplasia were yielded from our radiology archive, 171 of whom were diagnosed with Wilms tumor, 4 with angiomyolipoma and one with nephrogenic rest. The remaining 31 patients with a diagnosis of primary kidney neoplasia were enrolled in this retrospective study. Imaging data, age, gender, prognosis and findings regarding follow-up were noted.

RESULTS

Eight patients had renal cell carcinoma, seven had clear cell sarcoma, six had mesoblastic nephroma, four had rhabdoid tumor, three had desmoplastic small round cell tumor, two had cystic nephroma and one had metanephric stromal tumor. The age of diagnosis was > 8 years for renal cell carcinoma and desmoplastic small round cell tumor, < 5 years for rhabdoid tumor and < 7 months for mesoblastic nephroma. There was no gender preference for any tumor type. The prognosis for rhabdoid tumor was extremely poor in that all the patients followed up in our institute were deceased, whereas no recurrence was found in other tumors. Translocation type renal cell carcinoma had lower T2-weighted signal intensity, mesoblastic nephroma was a predominantly cystic mass, clear cell sarcoma was generally larger at presentation and extensive amorphous calcifications were seen in desmoplastic small round cell tumor.

CONCLUSION

For the differential diagnosis of pediatric non-Wilms renal tumors, age is the most important factor, followed by propensity to metastasize/aggressive behavior of the mass. Knowledge of specific imaging findings of these tumors may help to narrow the differential diagnosis.

Contrast-Enhanced Ultrasound Features of Adult Xp11.2 Translocation Renal Cell Carcinoma: Differential Diagnosis With Three Main Renal Cell Carcinoma Subtypes

OBJECTIVES

To investigate the sonographic features in Xp11.2 translocation renal cell carcinoma (Xp11.2 tRCC) using both conventional ultrasound (US) and contrast-enhanced US (CEUS) and evaluate the usefulness of sonographic imaging characteristics to differentiate between Xp11.2 tRCC and the three common RCC subtypes.

METHODS

Thirty-four adult Xp11.2 tRCC patients who preoperatively underwent both conventional US and CEUS and had solitary renal lesions and pathological confirmation after surgery were enrolled. Control matched patients included 131 with clear cell RCC (ccRCC), 48 with papillary RCC (pRCC), and 35 with chromophobe RCC (chRCC). Conventional US and CEUS data of all patients were retrospectively analyzed and compared.

RESULTS

Xp11.2 tRCC was more common in young women. The echogenicity of Xp11.2 tRCC lesions was hypo- and isoechoic relative to the adjacent renal cortex. A higher frequency of calcification within tumors was detected in Xp11.2 tRCC, but the presence of color flow signal (26.5%, 9/34) was much lower. Regarding CEUS features relative to the adjacent renal cortex, synchronous wash-in (61.8%, 21/34), iso-enhancement at peak (55.9%, 19/34), and fast wash-out (50.0%, 17/34) were more common in Xp11.2 tRCC. Moreover, an integrated variables model based on these features could differentiate Xp11.2 tRCC from ccRCC, pRCC, and chRCC (area under the curve, sensitivity, and specificity: 0.934, 92.0%, and 86.0%; 0.907, 88.0%, and 87.0%; and 0.808, 65.0%, and 99.0%, respectively).

CONCLUSIONS

Combining conventional US and CEUS lesion features with clinical information may provide a feasible and effective method to differentiate Xp11.2 tRCC from ccRCC, pRCC, and chRCC.

Update in collecting duct carcinoma: Current aspects of the clinical and molecular characterization of an orphan disease

Collecting duct renal cell carcinoma (cdRCC), which until recently was thought to arise from the collecting ducts of Bellini in the renal medulla, is a rare and aggressive type of non-clear renal cell carcinoma (ncRCC), accounting for 1% of all renal tumors and with nearly 50% of patients being diagnosed with Stage IV disease. The median overall survival in this setting is less than 12 months. Several regimens of chemotherapies had been used based on morphologic and cytogenetic similarities with urothelial cell carcinoma described previously, although the prognosis still remains poor. The use of targeted therapies also did not result in favorable outcomes. Recent works using NGS have highlighted genomic alterations in SETD2, CDKN2A, SMARCB1, and NF2. Moreover, transcriptomic studies have confirmed the differences between urothelial carcinoma and cdRCC, the possible true origin of this disease in the distal convoluted tubule (DCT), differentiating from other RCC (e.g., clear cell and papillary) that derive from the proximal convoluted tubule (PCT), and enrichment in immune cells that may harbor insights in novel treatment strategies with immunotherapy and target agents. In this review, we update the current aspects of the clinical, molecular characterization, and new targeted therapeutic options for Collecting duct carcinoma and highlight the future perspectives of treatment in this setting.

6p.21 translocation renal cell carcinoma in the elderly: radiological findings mimicking fat poor angiomyolipoma or papillary renal cell carcinoma

6p21 translocation renal cell carcinoma (RCC) harboring TFEB gene fusion is a newly classified microphthalmia-associated transcription (MiT) factor-family translocation RCC with early onset. We present a case of 78-year-old man with a 6p21 translocation RCC that was diagnosed after partial nephrectomy for an incidental renal tumor on computed tomography (CT). Unenhanced CT showed a 20 mm, mildly low-density mass in the right kidney. Contrast-enhanced CT showed a heterogeneous and prolonged, mild enhancement in the tumor. On magnetic resonance imaging, the tumor showed iso-intensity within the renal parenchyma on T1-weighted-imaging (WI), low intensity on T2WI, and no restricted diffusion with low signal on diffusion-weighted imaging, with no clear tumor pseudocapsule. Fat poor angiomyolipoma and non-clear cell RCC were listed as differential diagnoses. Robot-assisted partial nephrectomy was successfully performed. Fluorescence in situ hybridization study of the resected tumor confirmed TFEB gene break, and the patient was diagnosed with a 6p21 translocation RCC. The patient is doing well without recurrence after 2.5 years of follow-up. Our patient is the oldest patient reported in previous literature.

Imaging analysis of 13 rare cases of renal collecting (Bellini) duct carcinoma in northern China: a case series and literature review

Background

Collecting (Bellini) duct carcinoma (CDC) is a highly malignant and rare kidney tumor. We report our 12-year experience with CDC and the results of a retrospective analysis of patients and tumor characteristics, clinical manifestations, and imaging features by computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT.

Methods

Retrospective examination of tumors between January 2007 and December 2019 identified 13 cases of CDC from three medical centers in northern China. All 13 patients underwent CT scan, among which eight underwent dynamic enhanced CT scan, two underwent PET/CT scan, and one underwent magnetic resonance cholangiopancreatography (MRCP) examination. The lesions were divided into nephritis type and mass type according to the morphology of the tumors.

Results

The study group included ten men and three women with an average age of 64.23 ± 10.74 years. The clinical manifestations were gross hematuria, flank pain, and waist discomfort. The mean tumor size was 8.48 ± 2.48 cm. Of the 13 cases, six (46.2%) were cortical-medullary involved type and seven (53.8%) were cortex–medullary–pelvis involved type. Eleven (84.6%) cases were nephritis type and two (15.4%) were mass type. The lesions appeared solid or complex solid and cystic on CT and MRI. The parenchymal area of the tumors showed isodensity or slightly higher density on unenhanced CT scan in the 13 cases. PET/CT in two cases showed increased radioactivity intake. Evidence of intra-abdominal metastatic disease was present on CT in nine (69.2%) cases.

Conclusions

The imaging characteristics of CDC differ from those of other renal cell carcinomas. In renal tumors located in the junction zone of the renal cortex and medulla that show unclear borders, slight enhancement, and metastases in the early stage, a diagnosis of CDC needs to be considered. PET/CT provides crucial information for the diagnosis of CDC, as well as for designing treatment strategies including surgery.

MiT family translocation renal cell carcinoma in an elderly male

Translocation-associated renal cell carcinoma (t-RCC) is a relatively uncommon subtype of renal cell carcinoma characterized by recurrent gene rearrangements involving the TFE3 or TFEB loci. TFE3 and TFEB are members of the microphthalmia transcription factor (MiT) family, which regulate differentiation in melanocytes and osteoclasts. Renal cell carcinomas (RCCs) associated with Xp11 translocations have gene fusions involving TFE3, which has multiple gene partners; RCCs with t(6:11) translocations have MALAT1-TFEB gene fusions. These tumors are histologically diverse, often have papillary, alveolar, and nested growth pattern with clear and eosinophilic cells and psammoma bodies and are seen commonly in children and young adults, accounting to 40% of pediatric RCCs and 1.6%-4% of adult RCCs. The mean and median patient age is 31 years. Thus, distinguishing t-RCC from its morphologic, immunophenotypic, and molecular mimics has important clinical implications. Directed ancillary testing is an essential aspect to t-RCC cases and may include a panel of immunohistochemical stains, such as PAX8, pancytokeratins, AMACR, CD10, and TFE-3. We, hereby report a case of TFE3 positiveXp11 translocation renal cell carcinoma in a 52-year-old male which is unusual.

Contrast-enhanced ultrasound findings of adult renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion: comparison with clear cell renal cell carcinoma and papillary renal cell carcinoma

BACKGROUND

To investigate the contrast-enhanced ultrasound (CEUS) findings of renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusion (Xp11.2/TFE3) in adult patients by comparison with those of clear cell RCC (ccRCC) and papillary RCC (pRCC).

METHODS

In total, 110 patients (110 renal masses) who underwent CEUS examinations were enrolled in this study. The cases included 18 Xp11.2/TFE3 RCCs, 60 ccRCCs and 32 pRCCs. All masses were confirmed by operative pathology. The CEUS imaging data of these patients were retrospectively analysed by two readers. The conventional US and CEUS features of Xp11.2/TFE3 RCC were compared with those of ccRCC and pRCC.

RESULTS

The age of the patients with Xp11.2/TFE3 RCC ranged from 20 to 68 years, with a mean age of 38.3 ± 16.3 years and a slight female predominance. The weighted kappa value that interprets the concordance between the interobserver agreement of the US and CEUS features ranged from 0.61 to 0.89. On conventional US and CEUS imaging of Xp11.2/TFE3 RCCs, the tumours were hypoechoic (6/18, 33.3%), isoechoic (8/18, 44.4%), and hyperechoic (4/18, 22.2%). The cystic component was present in 5 cases (27.8%), calcification was present in 9 cases (50.0%), and colour flow signal was present in 7 cases (38.9%). Most cases showed simultaneous wash-in (11/18, 61.1%); the peak enhancement showed hypoenhancement (6/18, 33.3%), isoenhancement (10/18, 55.6%), and hyperenhancement (2/18, 11.1%); most cases exhibited heterogeneous enhancement (12/18, 66.7%) and fast- or simultaneous-out (16/18, 88.9%); and a pseudocapsule was present in 6 cases (33.3%). In the multivariate logistic regression analysis, calcification and lower peak enhancement were more likely to be present in Xp11.2/TFE3 RCC than in ccRCC (P < 0.05), and younger age and relatively high peak enhancement were more likely to be present in Xp11.2/TFE3 RCC than in pRCC (P < 0.05). The calcification combined peak enhancement model differentiated Xp11.2/TFE3 RCC from ccRCC, and the age combined peak enhancement model differentiated Xp11.2/TFE3 RCC from pRCC with an AUC, a sensitivity and a specificity of 0.896, 94.4% and 73.3% and 0.786, 50.0% and 100.0%, respectively.

CONCLUSIONS

The specific CEUS features combined with demographic information and clinical symptoms may be helpful for differentiating Xp11.2/TFE3 RCC from ccRCC and pRCC.

Magnetic resonance imaging findings of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion in adults: a pilot study

PURPOSE

The purpose of the study was to retrospectively analyze MRI findings of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion (Xp11.2/TFE RCC) in adults.

METHODS

Sixteen patients with Xp11.2/TFE RCC were reviewed retrospectively. The clinical characteristics and imaging features were assessed and then compared between metastatic and non-metastatic subgroups.

RESULTS

The mean age at diagnosis was 47.4 (20-76) years. Seven (44 %) patients were men, and nine (56 %) patients were women. The lesions predominantly exhibited an endophytic distribution (n = 14, 88 %) with a capsule (n = 16, 100 %), accompanied by solid and cystic patterns (n = 12, 75%) and hemorrhage (n = 11, 69 %). The tumors prevalently appeared hyper- to isointense on T1WI (n = 14, 88 %), hypointense on T2WI (n = 13, 81 %), and hyperintense on DWI (n = 16, 100 %) with a lower ADC (P < 0.001) than that of the surrounding tissue. The tumors were less enhanced than the normal renal cortex in all phases with a prolonged enhancement pattern (P ≤ 0.001). In addition, six patients (38 %) developed recurrence or metastases. The RCCs with metastases showed an irregular shape (P = 0.013), an incomplete capsule (P = 0.018), heterogeneous solid-cystic patterns (P = 0.034), and hemorrhage (P = 0.037) than non-metastatic subgroups.

CONCLUSIONS

MRI provides valuable information for the diagnosis of adult Xp11.2/TFE RCCs. Features including irregular shape, incomplete capsule, mixed solid-cystic pattern, and hemorrhage may indicate the occurrence of recurrence or metastases.

Adult-onset renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion: 3 case reports and review of literature

RATIONALE

Renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions is a rare subtype of renal cell carcinoma. This predominantly occurs in juveniles, but rarely seen in adults with lymph node or organic metastasis and a worsened prognosis.

PATIENTS CONCERNS

Herein, we presented 3 adult cases of Xp11-RCC. Two patients were in early stage and good condition, and the third patient had lymph node metastasis but showed no recurrence after a 3-month follow-up.

DIAGNOSES

Case 1: A 50-year-old female without any lumbago and gross hematuria was incidentally detected by left renal mass by ultrasonography. Case 2: A 31-year-old female with 2-year hemodialysis was detected with right renal carcinoma during preoperative examination of renal transplant. Case 3: A 45-year-old male with right lumbago for 1 month was detected with a mass in the lower pole of right kidney by ultrasonography.

INTERVENTION

The characteristics of these 3 images are not consistent with each other, and showed some differences with the previous ones.

OUTCOMES

All these 3 patients underwent laparoscopic radical nephrectomy, and case 1 patient underwent renal hilar lymphnode dissection at the same time. Immunohistochemistry was performed on all the 3 tumors, revealing that the tumor cells were positive for TFE3 and Melan-A. Case 1 showed lymph node metastasis, and received mTOR inhibitors. The 3 patients had no recurrent and new metastasis in other organs after follow-up for 3 months, 2 months, and 11 months, respectively.

LESSONS

Whether the adult-onset Xp-RCC has an aggressive clinical course still remains controversial. Characteristics of the images of the 3 adult cases showed some uniformity but still have some differences. Immunohistochemistry results revealed tumor cell positive for TFE3, but have no consistency in carbonic anhydrase IX, CD117, Ki67, CK8/18 AE1/AE3 and so on. Therefore, the uniform and definitive diagnostic standards of the tumors are uncertain. Hence, more cases and findings are required to elaborate the standards of all the tumor subtypes. Vascular endothelial growth factor-targeted therapy showed some efficacious results in patients with metastasis, but more useful treatments are warranted.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 2. The 2nd Decade: From the Radiologic Pathology Archives

Malignant renal tumors account for 7% of childhood cancers, and Wilms tumors are by far the most common-but not in older children and adolescents. Among individuals in the latter half of their 2nd decade of life, renal cell carcinoma (RCC) is more common than Wilms tumor. The histopathologic spectrum of RCCs in children differs from that in adults. The most common subtype of RCC in children and adolescents is Xp11.2 translocation RCC, which is distinguished by hyperattenuation at nonenhanced computed tomography, a defined capsule, and associated retroperitoneal lymphadenopathy. Papillary RCC is the second most common histologic subtype. It enhances less intensely compared with the adjacent renal parenchyma and has a propensity for calcification. Clear cell RCC is seen in patients with von Hippel-Lindau disease and is distinguished by its relatively hypervascular nature. Medullary carcinoma affects adolescents with the sickle cell trait and is characterized by an infiltrative growth pattern and extensive metastasis at presentation. Angiomyolipoma is seen in children with tuberous sclerosis complex and is often multifocal and hypervascular, with macroscopic fat. Metanephric tumors are central, circumscribed, and typically calcified. Lymphoma usually manifests as multifocal masses, but it may involve a solitary mass or infiltrative pattern. Extensive adenopathy and involvement of the gastrointestinal tract or other organs also may be seen. Primitive neuroectodermal tumor is an aggressive neoplasm that is typically quite large at diagnosis. Knowledge of the clinical, biologic, and histopathologic features of renal tumors in older children and adolescents and their effects on the imaging appearance can help the radiologist offer a useful preoperative differential diagnosis.

Diagnosis of Renal Angiomyolipomas: Classic, Fat-Poor, and Epithelioid Types

With the increasing discovery of small renal masses with cross-sectional imaging, there has been the concomitant rise in their treatment. With the intent of early curative surgery for a presumed renal cell carcinoma, many renal masses are being resected at surgery without a confirmed diagnosis. Many of them are benign, and some are angiomyolipomas. The diagnosis of renal angiomyolipoma using imaging is, therefore, is as important as ever. Although most, if not all angiomyolipomas with abundant fat are diagnosed readily, some have too little fat to be detected with imaging. This article reviews the current classification, imaging pitfalls, and diagnosis of angiomyolipoma with an emphasis on the fat-poor types. Proper imaging technique, a thorough search for fat, and the appropriate use of percutanoeus biopsy are all needed to eliminate the unnecessary treatment of these benign neoplasms.

Comparative study of CT appearances in renal oncocytoma and chromophobe renal cell carcinoma

BACKGROUND

Renal oncocytoma (RO) and chromophobe renal cell carcinoma (ChRCC) share histologic and some imaging features.

PURPOSE

To investigate the multidetector computed tomography (MDCT) characteristics of these two tumor types.

MATERIAL AND METHODS

Fifty-six patients with RO and 54 patients with ChRCC were studied retrospectively. MDCT was undertaken to investigate differences in tumor characteristics.

RESULTS

Calcifications were visible in 24 (42.8%) patients with RO and in 11 (20.4%) patients with ChRCC (P = 0.011). 26 patients with RO had stellate scars as did 14 patients with ChRCC (P = 0.025). Spoken-wheel-like enhancement was visible in 41 patients with RO and in 11 with ChRCC (P < 0.001). Thirty-nine (69.6%) patients with RO and nine (16.7%) patients with ChRCC showed segmental inversion (P < 0.001). Two patients with RO had retroperitoneal lymph node enlargement as did 13 patients with ChRCC (P = 0.002). Combined evaluation of stellate scar, spoken-wheel-like enhancement, and segmental enhancement inversion features were found to have a sensitivity of 99.1% (106 of 107), a specificity of 100% (3 of 3), a positive predictive value of 100% (106 of 106), and a negative predictive value of 75% (3 of 4). The attenuation of RO tumors was greater than that of ChRCC tumors, normal renal parenchyma on unenhanced CT (P = 0.031). Enhancement was higher with RO than with ChRCC tumors in all phases (P = 0.021, < 0.001, and 0.007, respectively).

CONCLUSION

CT imaging features such as stellate scar, spoken-wheel-like enhancement, and segmental enhancement inversion were more common in RO and they may help in differentiating RO from ChRCC.

Dynamic Computed Tomographic Features of Adult Renal Cell Carcinoma Associated With Xp11.2 Translocation/TFE3 Gene Fusions: Comparison With Clear Cell Renal Cell Carcinoma

OBJECTIVE

To investigate the dynamic contrast-enhanced computed tomography (CT) characteristics of renal cell carcinoma associated with Xp11.2 translocation and TFE gene fusion (Xp11.2 RCC) by comparison with clear cell renal cell carcinoma (CCRCC).

METHODS

Dynamic contrast-enhanced CT images and clinical and pathological records of 20 adult patients with Xp11.2 RCC confirmed by TFE3 immunohistochemical and fluorescence in situ hybridization assay were retrospectively analyzed and compared with the findings of 21 contemporary CCRCCs.

RESULTS

Renal cell carcinoma associated with Xp11.2 translocation and TFE gene fusions often occurred in young (30.6 ± 8.6 years) patients with hematuria (9/20). They presented as well-defined (17/20) cystic-solid (17/20) mass with hemorrhage (8/20) and circular/rim calcifications (6/20). Dynamic contrast-enhanced CT showed heterogeneous moderate prolonged enhancement. A tumor-to-cortex attenuation ratio in corticomedullary phase less than 0.62 gave a sensitivity of 90.0% and a specificity of 92.9% in differentiating Xp11.2 RCC from CCRCC (area under the receiver operating characteristic curve = 0.957, P < 0.001).

CONCLUSIONS

Computed tomographic characteristics and dynamic contrast-enhanced patterns and index can differentiate Xp11.2 RCC from CCRCC.

Dynamic Contrast-Enhanced CT Characterization of Xp11.2 Translocation/TFE3 Gene Fusions versus Papillary Renal Cell Carcinomas

PURPOSE

To compare the differences of CT characteristics between renal cell carcinomas (RCCs) associated with Xp11.2 translocation/TFE3 gene fusions (Xp11.2 RCCs) and papillary cell renal cell carcinomas (PRCCs).

METHODS

CT images and clinical records of 64 patients (25 Xp11.2 RCCs, 15 type 1 and 24 type 2 PRCCs) were analyzed and compared retrospectively.

RESULTS

Xp11.2 RCC more frequently affected young (30.7 ± 8.7 years) women (16/25, 64%) with gross hematuria (12/25, 48%), while PRCC more frequently involved middle-aged (54.8 ± 11.1 years) men (28/39, 71.8%) asymptomatically. Xp11.2 RCC tended to be heterogeneous density with some showing circular calcification. Lesion sizes of Xp11.2 RCC (5.4 ± 2.2 cm) and type 2 PRCC (5.7 ± 2.5 cm) were significantly larger than that of type 1 PRCC (3.8 ± 1.8 cm). Xp11.2 RCC contained more cystic components (22/25, 88%) than type 1 PRCC (all solid) and type 2 PRCC (9/24, 36.0%). Type 1 PRCC (13/15, 86.7%) and Xp11.2 RCC (21/25, 84.0%) showed more clear boundary than type 2 PRCC (12/24, 50.0%).

CONCLUSION

CT features including diameter, boundary, attenuation, nature, and circular calcification of the tumor, combined with demographic information and symptoms, may be useful to differentiate Xp11.2 RCC from different subtypes of PRCC.

Renal cell carcinomas with t(6;11) (p21;q12): presentation of two cases with computed tomography findings

Renal cell carcinomas with t(6;11) (p21;q12) translocation are extremely rare and primarily affect children and young adults. To our knowledge, there has been no case report focusing on the imaging manifestations in the existing literature. Hence, we describe the computed tomography findings of two young adults.

Magnetic resonance imaging and computed tomography characteristics of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion

PURPOSE

To characterize Xp11.2 translocation renal cell carcinoma (RCC) using magnetic resonance imaging (MRI) and computed tomography (CT).

METHODS

This study retrospectively collected the MRI and CT data of twelve patients with Xp11.2 translocation RCC confirmed by pathology. Nine cases underwent dynamic contrast-enhanced MRI (DCE-MRI) and 6 cases underwent CT, of which 3 cases underwent MRI and CT simultaneously. The MRI and CT findings were analyzed in regard to tumor position, size, hemorrhagic, cystic or necrotic components, calcification, tumor density, signal intensity and enhancement features.

RESULTS

The age of the 12 patients ranged from 13 to 46 years (mean age: 23 years). T2WI revealed heterogeneous intensity, hyper-intensity, and slight hypo-intensity in 6 cases, 2 cases, and 1 case, respectively. On DCE-MR images, mild, moderate, and marked rim enhancement of the tumor in the corticomedullary phase (CMP) were observed in 1, 6, and 2 cases, respectively. The tumor parenchyma showed iso-attenuation (n = 4) or slight hyper-attenuation (n = 1) compared to the normal renal cortex on non-contrast CT images. Imaging findings were suggestive of hemorrhage (n = 4) or necrosis (n = 8) in the tumors, and there was evidence of calcification in 8 cases by CT (n = 3) and pathology (n = 8). On dynamic contrast-enhanced CT images, 3 cases and 1 case manifested moderate and strong CMP enhancement, respectively. Nine tumors by MRI and 4 tumors by CT showed prolonged enhancement. Three neoplasms presented at stage I, 2 at stage II, 3 at stage III, and 4 at stage IV according the 2010 AJCC staging criteria.

CONCLUSIONS

XP11.2 translocation RCC should be considered when a child or young adult patient presents with a renal tumor with heterogeneous features such as hemorrhage, necrosis, cystic changes, and calcification on CT and MRI and/or is accompanied by metastatic evidence.

MiT translocation renal cell carcinomas: two subgroups of tumours with translocations involving 6p21 [t (6; 11)] and Xp11.2 [t (X;1 or X or 17)]

INTRODUCTION

MiT translocation renal cell carcinomas (TRCC) predominantly occur in younger patients with only 25% of patients being over 40 years. TRCC contains two main subgroups with translocations involving 6p21 or Xp11.2. Herein we present 10 cases.

MATERIALS

Eight cases were treated at main author's institution (identified among 1653 (0.48%) cases of kidney tumours in adults). Two cases were retrieved from the Pilsen (CZ) Tumour Registry.

RESULTS

Six cases were type Xp11.2 and four 6p21; 7 female, 3 male patients; Xp11.2 4:2, 6p21 3:1. The mean age 49 years (range: 21-80), 5 patients (50%) over 40 years. The mean age of the group with Xp11.2 TRCCs was 55 (median 51) and 6p21 41 (32) years. One female with a 6p21 tumour (24 years) underwent nephrectomy at 4 months of pregnancy. Stage (UICC, 7th ed. 2009) was 5xI, 3xIII, 2xIV. The mean size of tumour was 80 (40-165) mm. The mean follow-up was 33.2 (1-92) months. In patients with 6p21 tumours, one (25%) died after 3 months due to widely metastatic disease. In patients with Xp11.2 tumours, 3 (50%) succumbed due to metastatic disease (range 1-8 months). Three patients with Xp11.2 are alive at 7, 52 and 92 months of follow-up, were diagnosed at early stage (T1a).

CONCLUSION

TRCCs were more common in females. Patient with 6p21 tumours were younger than those with Xp11.2. Both types have definitive malignant potential Type Xp11.2 seems to be a more aggressive neoplasm than 6p21. The case with metastatic 6p21 tumour is the 4th case described in the English literature.

Renal carcinomas associated with Xp11.2 translocations: are CT findings suggestive of the diagnosis?

AIM

The purpose of the present study was to summarize the computed tomography (CT) features of renal carcinomas associated with Xp11.2 translocations, and determine whether the diagnosis can be reliably deduced from imaging findings.

MATERIALS AND METHODS

Radiological studies of six patients (aged from 9-29 years) with renal carcinoma associated with Xp11.2 translocations were retrospectively analysed.

RESULTS

The tumours varied in size from 3.3-11 cm (mean 5.4 cm). Unenhanced CT and cortical, medullary, and pelvic-phase contrast-enhanced CT imaging was undertaken in all cases. Unenhanced CT revealed that tumours had a relatively increased radiodensity (4/6, ranged from 45-60 HU) and suggested the possibility of diffuse haemorrhage. Three of the six cases showed irregular and boundary calcification of the lesion. Contrast-enhanced CT showed relatively well demarcated tumours with heterogeneous enhancement (6/6). Prolonged enhancement of tumours might be a common sign (6/6) in Xp11.2 translocations. Three out of the six cases were combined with retroperitoneal lymph nodes metastasis.

CONCLUSION

Renal carcinomas associated with Xp11.2 translocations should be considered, particularly in children and young patients, when the lesion has calcification and is hyper-dense on unenhanced CT, and has prolonged enhancement on contrast-enhanced images.

Renal carcinomas associated with Xp11.2 translocations/TFE3 gene fusions: findings on MRI and computed tomography imaging

PURPOSE

To retrospectively analyze MRI and computed tomographic (CT) findings from renal carcinomas associated with Xp11.2 translocations/TFE3 gene fusions (Xp11-RCC).

MATERIALS AND METHODS

Institutional review board permission was obtained to review patient medical records, and the requirement for informed consent was waved . The clinical and MRI/CT features of five cases with Xp11-RCC that were confirmed by pathology were analyzed retrospectively. The image characteristics included the lesion location and size, contribution of cystic and solid components, intratumoral necrosis or hemorrhage, invasion of perinephric tissue and renal sinus, lymphadenopathy, major venous or arterial vascular invasion, pattern of the tumor growth, intratumor calcification and lipids, homogeneity of SI on T2-weighted images, attenuation and SI of the mass with respect to the normal renal cortex on precontrast and contrasted CT/MRI images, tumor SIs, tumor attenuations and tumor-to-cortex indices, homogeneity of enhancement on the contrasted images.

RESULTS

The mean age was 32 years (range, 15-47 years). Most patients (4/5) were women. All tumors showed a cortical location. The average tumor size was 9 cm (range, 4-18 cm). Four tumors comprised a predominantly solid lesion with focal necrosis, and one tumor comprised a solid lesion with significant necrosis. All tumors showed intertumor hemorrhage, infiltrative growth and invasion of the perirenal adipose/renal sinus. Four cases showed retroperitoneal lymphadenopathy, of which one case showed simultaneous mediastinal and supraclavicular lymphadenopathy. All tumors from four cases showed mild hyperintensity on T1-weighted MRI images, and three tumors showed hypointensity on T2-weighted MRI images relative to the renal cortex except for 1 tumor that showed significant hemorrhage and a relative hyperintensity. For 3 cases who were imaged with CT, two tumors imaged using nonenhanced CT images showed mild hyperdensity relative to the renal cortex. Calcification was noted in all three tumors. All tumors showed mild, persistent enhancement.

CONCLUSION

Typical Xp11-RCC manifests as an advanced, solid renal mass with mild persistent enhancement, a prevalence of intertumor hemorrhage/calcification, and a cortical epicenter location. The predilection for children and young adults is a useful clinical feature when confirming a diagnosis of Xp11-RCC.

Radiologic-pathologic correlation of renal cell carcinoma associated with Xp11.2 translocation

BACKGROUND

The prognosis of translocation RCCs in adult patients is relatively poor compared to that of other subtypes of RCCs. Although there have been several reports regarding radiologic findings of translocation RCC, studies with histologic correlation could help to understand the imaging features.

PURPOSE

To explore the correlation between radiologic and pathologic findings in Xp11.2 translocation renal cell carcinoma (RCC) and provide clues for translocation RCC diagnosis.

MATERIAL AND METHODS

CT scans of six patients (one man and five women; age range, 8-71 years; mean age, 34 years) with histologically-proven Xp11.2 translocation RCCs were retrospectively evaluated in consensus by two radiologists. Tumor size, presence of necrosis, hemorrhage, fat or calcification, enhancement patterns of the tumor, presence of lymphadenopathy, and distant metastases were evaluated.

RESULTS

The average size of the tumors was 6 cm (range, 2.7-12 cm). All six tumors appeared as well-defined masses with areas of low attenuation representing hemorrhage or necrosis. Four tumors contained high attenuating solid portions, compared to the surrounding renal cortex seen on unenhanced images, where representing dense cellular component on microscopic examination. Peripheral rim enhancement pattern that correlated with histologic finding of a fibrous capsule was seen in five cases. In two patients who underwent kidney MR, the masses showed low signal intensity on T2-weighted images. One patient had lymphadenopathy. No distant metastasis was noted in any patient.

CONCLUSION

Translocation RCC appeared as a well-defined mass that contain high attenuating solid portions on unenhanced images and low attenuating necrotic or hemorrhagic foci; the tumor also showed gradual peripheral rim enhancement due to a fibrous capsule surrounding the tumor.

The MSCT and MRI findings of collecting duct carcinoma

AIM

To characterize the multi-section computed tomography (MSCT) and magnetic resonance imaging (MRI) features of collecting duct carcinoma (CDC).

MATERIALS AND METHODS

Twenty patients with CDC were studied retrospectively using MSCT (n = 20), and MSCT and MRI (n = 5). MSCT and MRI were undertaken to investigate tumour location, size, radiodensity, cystic or solid appearance, calcification, capsule, signal, enhancement pattern, and metastases.

RESULTS

Tumours (mean diameter 3.6 ± 1.7 cm) were solitary (20/20), solid (18/20), had cystic components (12/20), calcifications (12/20), poorly defined (18/20), were centred in the medulla (20/20), compressed the renal pelvis (12/20), and had lymph node metastases (2/20). On unenhanced computed tomography (CT), the radiodensity of the CDC was greater than that of the normal renal cortex or medulla (43.8 ± 2.4 versus 37.6 ± 5.1 or 32.6 ± 4.1, p = 0.041, n = 20). Five patients with CDC underwent MRI, which revealed cystic components (4/5), poorly defined CDC (5/5), and none of the patients had lymph node metastasis. The CDC was isointense on T1-weighted imaging, and iso- or hypointense on T2-weighted imaging. Enhancement was lower within the CDC than the renal cortex and medulla during all enhanced phases (p = 0.032, 0.001, 0.018, respectively, n = 20).

CONCLUSION

CDC should be considered when a renal tumour is centred in the medulla, with increased radiodensity on unenhanced CT and reduced enhancement compared to the adjacent cortex or medulla.

The multislice CT findings of renal carcinoma associated with XP11.2 translocation/TFE gene fusion and collecting duct carcinoma

BACKGROUND

Renal cell carcinoma associated with Xp11.2 translocation and TFE gene fusion (Xp11.2/TFE RCC), and collecting duct carcinoma (CDC) are uncommon subtypes of renal cell carcinomas.

PURPOSE

To investigate the multislice CT (MSCT) characteristics of these two tumor types.

MATERIAL AND METHODS

Nine patients with Xp11.2/TFE RCC and 10 patients with CDC were studied retrospectively. MSCT was undertaken to investigate differences in tumor characteristics and enhancement patterns.

RESULTS

All patients had single tumors centered in the renal medulla. Two patients with each tumor type had lymph node involvement and there was a single case of hepatic metastasis (Xp11.2/TFE RCC). The mean tumor diameter of Xp11.2/TFE RCC tumors was significantly larger than for CDC tumors. Two patients with Xp11.2/TFE RCC had cystic components as did eight patients with CDC (P < 0.05). Calcifications were present in six patients, each with CDC. Clear tumor boundaries were visible in two patients with CDC and in nine with Xp11.2/TFE RCC (P < 0.05). The density of Xp11.2/TFE RCC tumors was greater than that of CDC tumors, normal renal cortex, or medulla on unenhanced CT. Enhancement was higher with Xp11.2/TFE RCC than with CDC tumors during all phases. Xp11.2/TFE RCC enhancement was higher than in the renal medulla during cortical and medullary phase but lower than in normal renal medulla during the delayed phase. CDC tumor enhancement was lower than that for normal renal medulla during all enhanced phases.

CONCLUSION

Both tumor types originated from the renal medulla. Distinguishing features included density on unenhanced CT, enhancement patterns, and capsule signs. Identifying these differences may aid diagnosis.

WITHDRAWN: Comparative study of CT appearances in renal carcinoma associated with Xp11.2 translocation/TFE gene fusion and papillary renal cell carcinoma

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Rare (<1%) histological subtypes of renal cell carcinoma: an update

Recent advances in genetics and pathology have allowed description of several new histological subtypes of renal cell carcinoma (RCC) as well as better characterization of other rare subtypes. We herein present a comprehensive review of taxonomy, epidemiology, pathology, imaging findings, and natural history of a wide spectrum of rare subtypes of RCCs that individually constitute <1% of all the RCCs.