Avelumab plus axitinib for translocation renal cell carcinoma: A case series and literature review

Introduction

Patients with translocation renal cell carcinoma (tRCC) have a poor prognosis without standardized treatment.

Case presentation

The first case was of a 72-year-old woman who underwent robot-assisted partial nephrectomy for a left renal tumor and was pathologically diagnosed with tRCC. Recurrence was observed in the left retroperitoneal soft tissue. After treatment with avelumab-axitinib, continued progression-free survival was confirmed at the 90-week follow-up. The second case was of a 41-year-old woman referred to our hospital and presented with translocation renal cell carcinoma metastasis to a para-aortic lymph node. After treatment with avelumab-axitinib, continued progression-free survival was confirmed at the 43-week follow-up.

Conclusion

The outcomes of these cases indicate that avelumab-axitinib therapy has a long-term antitumor effect in some patients with tRCC.

Renal cell carcinoma in the contralateral kidney with TFE3 gene translocation following chemotherapy for childhood nephroblastoma: A case report and literature review

Key Clinical Message

Renal cell carcinoma as a secondary malignant neoplasm is relatively rare; however, the possibility of secondary renal cell carcinoma following chemoradiotherapy for childhood nephroblastoma should be considered.

Abstract

The occurrence of secondary renal cell carcinoma (RCC) following chemoradiotherapy for nephroblastoma is relatively rare, especially in microphthalmia transcription factor family translocation renal cell carcinoma. A 13-year-old Japanese male was referred to our department for treatment of a right kidney mass. The patient had undergone open left nephrectomy and adjuvant chemotherapy for nephroblastoma, 12 years before. Diagnostic imaging revealed a tumor in the right kidney and a lesion suspected to be metastasis in the left eighth rib. Chromophobe RCC or translocation RCC was suspected from the imaging pattern. TNM classification was cT1aN0M1, and the clinical stage was IV. Partial nephrectomy by robot-assisted surgery for the right renal tumor and resection of the left eighth rib were performed. Pathologically, the renal tumor was diagnosed as translocation RCC, and the rib lesion demonstrated no evidence of malignancy. We are currently undergoing imaging follow-up and the patient has been recurrence-free for 15 months. In this study, we present a rare case of secondary translocation RCC after successful treatment of nephroblastoma.

Multimodality imaging of Xp11.2 translocation/TFE3 gene fusion associated with renal cell carcinoma: a case report

Background

Xp11.2 translocation/TFE3 gene fusion associated with renal cell carcinoma (Xp11.2 RCC) exhibits unique biological characteristics and is associated with an increased incidence of tumor thrombosis, lymph node metastasis, and advanced disease stages. Multimodality imaging, including US, contrast-enhanced CT, multi-parametric MRI, and 18F-FDG PET/CT plays a crucial role in the preoperative diagnosis and differentiation of renal tumors.

Case report

A 15-year-old female presented with lumbar pain worsened, and developed persistent painless hematuria. The CT attenuation values of the scan without contrast, corticomedullary phase, nephrographic phase, and delayed phases were 35 HU, 83 HU, 82 HU, and 75 HU, respectively. The solid component of the mass displayed heterogeneous marked enhancement. Furthermore, MRU indicated that the lesion involved the cortical medulla and infringed on the renal sinus fat. The lesion appeared isosignal in T1WI, slightly low signal in T2WI, and slightly high signal in DWI. The degree of enhancement in the three phases of enhancement scan was lower than that in the renal parenchyma, and hemorrhage and necrosis were observed within the internal part of the lesion. To further clarify the staging, the patient underwent 18F-FDG PET/CT. PET/CT images showed multiple irregular occupancies in the right kidney with unclear borders, showing a heterogeneous increase in 18F-FDG uptake, with SUVmax values ranging from 2.3 to 5.2 in the routine imaging phase (60 min post-injection), compared to SUVmax values ranging from 2.8 to 6.9 in the delayed imaging phase (160 min post-injection). Additionally, multiple enlarged and fused lymph nodes were observed in the medial part of the right kidney and the retroperitoneum, exhibiting a heterogeneous increase in 18F-FDG uptake, with SUVmax values ranging from 4.1 to 8.7 in the routine imaging phase, compared to SUVmax values ranging from 4.4 to 9.1 in the delayed imaging phase. The postoperative pathology, immunohistochemistry, and molecular analysis of histiocytes were consistent with a diagnosis of Xp11.2 RCC. One month after surgery, enhanced-CT examination of the patient revealed lung metastasis, peritoneal metastasis, and multiple lymph node metastases throughout the body, with an overall survival of 16 months.

Conclusion

Xp11.2 RCC exhibits unique biological characteristics and is associated with an increased incidence of tumor thrombosis, lymph node metastasis, and advanced disease stages. Long-term follow-up is essential to monitor the likelihood of recurrence and metastasis. 18F-FDG PET/CT examination can comprehensively visualize the lesion's location and extent, providing a basis for clinical tumor staging and aiding in treatment monitoring and follow-up. To address the limitations of FDG, the utilization of specific tracers designed for RCC or tracers that are not excreted via the urinary system would be ideal. Further advancements in molecular imaging technologies and the development of novel tracers hold great promise in advancing the diagnosis and management of RCC, ultimately contributing to better patient outcomes and overall disease management.

"Papillary Adenoma-like" Renal Tumor with TFE3 Gene Rearrangement, A Potential Precursor to or Early Event in the Development of TFE3 Translocation Renal Cell Carcinoma

MiT family translocation renal cell carcinomas harbor gene fusion involving members of MiT family of transcription factors. Their precursor lesions have not been identified. Herein, we report the first case of small papillary tumors morphologically resembling papillary adenomas but harboring TFE3 gene alteration. The patient was a 23-year old man with multiple small papillary tumors in the right kidney discovered following a gunshot wound injury. These lesions were < 5 mm, well-circumscribed but not encapsulated tubulopapillary proliferation lined with a single layer of cuboidal cells with WHO/ISUP grade 1 or 2 nuclei. The tumor cells were immunoreactive to PAX8, AMACR, high molecular weight cytokeratin, and keratin 7 and negative for CD10, CA9, TTF1, and cathepsin K. Morphologically and immunohistochemically, these lesions were diagnosed as papillary adenomas. TFE3 gene rearrangement was confirmed by fluorescence in-situ hybridization (FISH) using a TFE3 break-apart probe. We term these tumors "papillary adenoma-like" renal tumor with TFE3 gene rearrangement. These tumors are likely a precursor to or represent an early event in the development of TFE3 translocation renal cell carcinomas. An understanding of such tumors to translocation renal cell carcinoma progression can provide insight into the pathogenic mechanism, and ultimately aid the diagnosis and management of translocation renal cell carcinoma.

Integrative clinical and molecular characterization of translocation renal cell carcinoma

Translocation renal cell carcinoma (tRCC) is a poorly characterized subtype of kidney cancer driven by MiT/TFE gene fusions. Here, we define the landmarks of tRCC through an integrative analysis of 152 patients with tRCC identified across genomic, clinical trial, and retrospective cohorts. Most tRCCs harbor few somatic alterations apart from MiT/TFE fusions and homozygous deletions at chromosome 9p21.3 (19.2% of cases). Transcriptionally, tRCCs display a heightened NRF2-driven antioxidant response that is associated with resistance to targeted therapies. Consistently, we find that outcomes for patients with tRCC treated with vascular endothelial growth factor receptor inhibitors (VEGFR-TKIs) are worse than those treated with immune checkpoint inhibitors (ICI). Using multiparametric immunofluorescence, we find that the tumors are infiltrated with CD8⁺ T cells, though the T cells harbor an exhaustion immunophenotype distinct from that of clear cell RCC. Our findings comprehensively define the clinical and molecular features of tRCC and may inspire new therapeutic hypotheses.

Cathepsin K: A Novel Diagnostic and Predictive Biomarker for Renal Tumors

Simple Summary

Our understanding of renal tumors has increased in the last years with the description of several novel entities. The expanding morphological spectrum complicates the pathologist’s diagnosis, often requiring immunohistochemical analysis. The role of cathepsin K immunoexpression is widened as a diagnostic tool in several renal tumors. This review describes the usefulness of cathepsin K in the differential diagnosis of renal neoplasms, highlighting the biological knowledge underpinning its expression. Moreover, cathepsin K seems to be a downstream marker of different genetic alterations, with a possible role as a predictive marker that may prospectively guide the development of therapeutic approaches as a molecular target.

Abstract

Cathepsin K is a papain-like cysteine protease with high matrix-degrading activity. Among several cathepsins, cathepsin K is the most potent mammalian collagenase, mainly expressed by osteoclasts. This review summarizes most of the recent findings of cathepsin K expression, highlighting its role in renal tumors for diagnostic purposes and as a potential molecular target. Indeed, cathepsin K is a recognized diagnostic tool for the identification of TFE3/TFEB-rearranged renal cell carcinoma, TFEB-amplified renal cell carcinoma, and pure epithelioid PEComa/epithelioid angiomyolipoma. More recently, its expression has been observed in a subgroup of eosinophilic renal neoplasms molecularly characterized by TSC/mTOR gene mutations. Interestingly, both TSC mutations or TFE3 rearrangement have been reported in pure epithelioid PEComa/epithelioid angiomyolipoma. Therefore, cathepsin K seems to be a downstream marker of TFE3/TFEB rearrangement, TFEB amplification, and mTOR pathway activation. Given the established role of mTOR inhibitors as a pharmacological option in renal cancers, cathepsin K could be of use as a predictive marker of therapy response and as a potential target. In the future, uropathologists may implement the use of cathepsin K to establish a diagnosis among renal tumors with clear cells, papillary architecture, and oncocytic features.

Targeted therapy in Xp11 translocation renal cell carcinoma

BACKGROUND

Translocation renal cell carcinoma (TRCC) is a rare form of RCC affecting mostly children and young adults with the occurrence of only 1-5% of all renal cell carcinomas. These carcinomas are associated with different translocations on a short arm of chromosome X in the region 11.2, which results in genetic modification of the p arm containing the transcription factor E3 gene.

METHODS

Herein we report a case of a patient who was dia-gnosed with TRCC with c-Met overexpression and was treated with multiple targeted therapy agents and immunotherapy.

CASE

A 28-year old woman without a significant past medical history underwent left sided total nephrectomy for TRCC. Seven months later, she developed systemic relapse and was treated with multiple lines of targeted therapy including sunitinib, everolimus, sorafenib, crizotinib, and pazopanib as well as with anti-PD-L1 antibody nivolumab, with stable disease as a best response. The most pronounced disease stabilization was achieved with sorafenib, which lasted 18 months. The patient died 81 months after initial dia-gnosis and 74 months from the dia-gnosis of metastatic disease.

CONCLUSION

Improved survival observed in our patient could be related to the effectivity of tyrosine-kinase inhibitors, but notm-TOR inhibitors, even though disease stabilisation was observed as a best response. Identification of new treatment targets are warranted in this rare disease.

A prospective study of pediatric and adolescent renal cell carcinoma: A report from the Children's Oncology Group AREN0321 study

BACKGROUND

To the authors' knowledge, AREN0321 is the first prospective clinical study of pediatric and adolescent renal cell carcinoma (RCC). Goals of the study included establishing epidemiological, treatment, and outcome data and confirming that patients with completely resected pediatric RCC, including lymph node-positive disease (N1), have a favorable prognosis without adjuvant therapy.

METHODS

From 2006 to 2012, patients aged <30 years with centrally reviewed pathology of RCC were enrolled prospectively.

RESULTS

A total of 68 patients were enrolled (39 of whom were male; median age of 13 years [range, 0.17-22.1 years]). Stage was classified according to the American Joint Committee on Cancer TNM stage seventh edition as stage I in 26 patients, stage II in 7 patients, stage III in 26 patients, and stage IV in 8 patients, and was not available in 1 patient. Sixty patients underwent resection of all known sites of disease, including 2 patients with stage IV disease. Surgery included radical nephrectomy (53 patients [81.5%]), partial nephrectomy (12 patients [18.5%]), and unknown (3 patients [4.4%]). Histology was TFE-associated RCC (translocation-type RCC; tRCC) in 40 patients, RCC not otherwise specified and/or other in 13 patients, papillary RCC in 9 patients, and renal medullary carcinoma (RMC) in 6 patients. Lymph node status was N0 in 21 patients, N1 in 21 patients (tRCC in 15 patients, RMC in 3 patients, papillary RCC in 2 patients, and not otherwise specified and/or other in 1 patient), and Nx in 26 patients. The 4-year event-free survival and overall survival rates were 80.2% (95% CI, 69.6%-90.9%) and 84.8% (95% CI, 75.2%-94.5%), respectively, overall and 87.5% (95% CI, 68.3%-100%) and 87.1% (95% CI, 67.6%-100%), respectively, for the 16 patients with N1M0 disease. Among patients presenting with metastases, 2 of 8 patients (2 of 5 patients with RMC) were alive (1 with disease) at the time of last follow-up, including 1 patient who was lost to follow-up (succinate dehydrogenase deficiency). The predominant RCC subtypes associated with mortality were tRCC and RMC.

CONCLUSIONS

Favorable short-term outcomes can be achieved without adjuvant therapy in children and adolescents with completely resected RCC, independent of lymph node status. A prospective study of patients with tRCC and RMC with M1 or recurrent disease is needed to optimize treatment.

Clinicopathological characterisation of renal cell carcinoma in young adults: a contemporary update and review of literature

AIMS

Renal cell carcinomas are relatively rare in children and young adults. While well characterised in adults, the morphological and molecular characterisation of these tumours in young patients is relatively lacking. The objective of this study was to explore the spectrum of renal cell carcinoma (RCC) subtypes in children and young adults and to determine their clinico-pathological, immunohistochemical and molecular characteristics by evaluating a large retrospective cohort of renal cell carcinoma patients age 30 years or younger.

METHODS AND RESULTS

Sixty-eight cases with confirmed diagnosis of renal cell carcinoma at age 30 years or younger were identified at our institution. Clear cell carcinoma accounted for the most common subtype seen in this age group. Translocation renal cell carcinoma and rare familial syndrome subtypes such as succinate dehydrogenase deficient renal cell carcinoma and tuberous sclerosis complex-associated renal cell carcinoma were found relatively more frequently in this cohort. Despite applying the 2016 WHO classification criteria, a high proportion of the tumours in our series remained unclassified.

CONCLUSIONS

Our results suggest that renal cell carcinoma in children and young adults is a relatively rare disease that shares many histological similarities to renal cell carcinoma occurring in adults and yet demonstrate some unique clinical-pathological differences. Microphthalmia-associated transcription (MiT) family translocation RCC and rare familial syndrome subtypes are relatively more frequent in the paediatric and adolescent age groups than in adults. Clear cell RCC still accounted for the most common subtype seen in this age group. MiT family translocation RCC patients presented with advanced stage disease and had poor clinical outcomes. The large and heterogeneous subgroup of unclassified renal cell carcinoma contains phenotypically distinct tumours with further potential for future subcategories in the renal cell carcinoma classification.

PD-L1 expression and infiltration by CD4+ and FoxP3+ T cells are increased in Xp11 translocation renal cell carcinoma and indicate poor prognosis

AIMS

Interaction between programmed death-1 ligand (PD-L1) and its receptor programmed death 1 (PD-1) on T cells inactivates antitumour immune responses. PD-L1 expression has been associated with poor prognosis in renal cell carcinoma (RCC) and predicts adverse outcome. This study was designed to evaluate the impact of PD-L1 expression and the immune microenvironment on the clinical outcome in Xp11 translocation renal cell carcinoma (TRCC) and, therefore, their potential relevance as prognostic biomarkers.

METHODS AND RESULTS

The present retrospective analysis investigated expression of PD-L1 and immune cells CD8, CD4, CD3, forkhead box protein 3 (FoxP3) and PD-1 in TRCC compared to other types of RCC. FFPE specimens were collected between 2011 and 2017 from 311 patients who underwent nephrectomy at our institution for RCC. Specimens were immunostained for PD-L1, CD8, CD4, CD3, FoxP3 and PD-1, and an outcome analysis was conducted. PD-L1 expression rate was highest in TRCC (68%, 16 of 25), followed by mucinous tubular and spindle cell RCC and collecting duct carcinoma (33%, one of three), papillary RCC (27%, seven of 26), clear cell RCC (16%, 29 of 233), chromophobe RCC (11%, two of 18) and multilocular cystic RCC (0%, none of three). In TRCC, PD-L1 expression was associated with poor recurrence-free survival (RFS) (P = 0.041). The CD4^high and FoxP3^high groups showed a significantly shorter RFS (P = 0.05 and P = 0.031, respectively) compared to CD4^low and FOXP^low groups.

CONCLUSION

PD-L1 expression was higher in TRCC than in other types of RCC. High PD-L1 tumour cell expression and tumour infiltration by CD4⁺ and FoxP3⁺ immune cells were associated with poor RFS in TRCC.

Gene fusion analysis in renal cell carcinoma by FusionPlex RNA-sequencing and correlations of molecular findings with clinicopathological features

Translocation renal cell carcinoma (tRCC) affects younger patients and often presents as advanced disease. Accurate diagnosis is required to guide clinical management. Here we evaluate the RNA-sequencing FusionPlex platform with a 115-gene panel including TFE3 and TFEB for tRCC diagnosis and correlate molecular findings with clinicopathological features. We reviewed 996 consecutive RCC cases from our institution over the preceding 7 years and retrieved 17 cases with histological and immunohistochemical features highly suggestive of either TFE3 (n = 16) or TFEB (n = 1). Moderate to strong labeling for TFE3 was present in 15 cases; two cases with weak TFE3 expression were melan-A or cathepsin-K positive. RNA-sequencing detected gene rearrangements in eight cases: PRCC-TFE3 (3), ASPSCR1-TFE3 (2), LUC7L3-TFE3 (1), SFPQ-TFE3 (1), and a novel SETD1B-TFE3 (1). FISH assays of 11 tumors verified six positive cases concordant with FusionPlex analysis results. Two other cases were confirmed by RT-PCR. FusionPlex was superior to FISH by providing precise breakpoints for tRCC-related genes in a single assay and allowing identification of both known and novel fusion partners, thereby facilitating clinicopathological correlations as fusion partners can influence tumor appearance, immunophenotype, and behavior. Cases with partner genes PRCC and novel partner SETD1B were associated with prominent papillary architecture while cases with partner genes ASPSCR1 and LUC7L3 were associated with a predominantly nested/alveolar pattern. The case with SFPQ-TFE3 fusion was characterized by biphasic morphology mimicking TFEB-like translocation RCC. We recommend FusionPlex analysis of RCC in patients under age 50 or when the histologic appearance suggests tRCC.

Treatment of advanced pediatric renal cell carcinoma

BACKGROUND

Pediatric renal cell carcinoma (pRCC) is the second most common renal malignancy of childhood; however, treatment data for advanced disease is lacking.

METHODS

A retrospective analysis of pRCC patients (age < 21 years at diagnosis) treated between 2000 and 2015 at Cincinnati Children's Hospital Medical Center was undertaken, with specific focus on medical therapies, accompanied by a detailed literature review.

RESULTS

Twenty-four patients (median age = 15 years) were identified; 11 were female. Past history of kidney pathology (4) and prior hematologic/oncologic diagnoses (5) were common associated findings. Translocation morphology RCC (tRCC) was the most common subtype (16; 64%), followed by papillary (6; 24%), clear cell renal cell carcinoma (ccRCC) (1), and chromophobe (1). The TNM stage distribution was I (8; 33%), II (2; 8%), III (3; 13%), and IV (11; 46%). Eleven patients with stage IV disease all had tRCC and received medicinal anticancer therapies, the most common being antiangiogenic (10), conventional chemotherapy (8), mTOR inhibition (7), and immunotherapy (3). Four patients also received small-port radiotherapy. The mean time to progression (TTP) was longest for axitinib (n = 2; TTP = 7.8 m; range 5.5-10 m) and sunitinib (n = 6; TTP = 4.7 m; range 0.3-12 m). Overall, 20 cases of pediatric RCC who received RCC-directed medicinal therapy with outcome data have been previously reported.

CONCLUSIONS

For patients with unresectable pRCC requiring systemic therapy, available data are scarce. Data herein support an increased TTP with antiangiogenic therapy in tRCC supporting a formal study of antiangiogenic therapies through multicooperative-group collaboration.

The classification of pediatric and young adult renal cell carcinomas registered on the children's oncology group (COG) protocol AREN03B2 after focused genetic testing

BACKGROUND

Renal cell carcinomas (RCCs) are rare in young patients. Knowledge of their pathologic and molecular spectrum remains limited, and no prospective studies have been performed to date in this population. This study analyzes patients diagnosed with RCC who were prospectively enrolled in the AREN03B2 Children's Oncology Group (COG). The objective was to classify these tumors with the aid of focused genetic testing and to characterize their features.

METHODS

All tumors registered as RCC by central review were retrospectively re-reviewed and underwent additional ancillary studies. Tumors were classified according to the 2016 World Health Organization classification system when possible.

RESULTS

In total, 212 tumors were identified, and these were classified as microphthalmia transcription factor (MiT) translocation RCC (MiT-RCC) (41.5%), papillary RCC (16.5%), renal medullary carcinoma (12.3%), chromophobe RCC (6.6%), clear cell RCC (3.3%), fumarate hydratase-deficient RCC (1.4%), and succinate dehydrogenase-deficient RCC (0.5%). Other subtypes included tuberous sclerosis-associated RCC (4.2%), anaplastic lymphoma kinase (ALK)-rearranged RCC (3.8%), thyroid-like RCC (1.4%), myoepithelial carcinoma (0.9%), and unclassified (7.5%). MiT-RCCs were classified as either transcription factor E3 (TFE3) (93.2%) or EB (TFEB) (6.8%) translocations, and characterization of fusion partners was possible in most tumors.

CONCLUSIONS

The current study delineates the frequency of distinct RCC subtypes in a large prospective series of young patients and contributes knowledge to the diagnostic, clinical, and genetic features of MiT-RCC, the most common subtype among this age group. The identification of rare subtypes expands the spectrum of RCC in young patients, supporting the need for a thorough diagnostic workup. These studies may aid in the introduction of specific therapies for different RCC subtypes in the future. Cancer 2018. © 2018 American Cancer Society.

Characterization of adolescent and pediatric renal cell carcinoma: A report from the Children's Oncology Group study AREN03B2

BACKGROUND

The current study was conducted to characterize the epidemiology, histology, and radiographic features of as well as the surgical approach to pediatric and adolescent renal cell carcinoma (pRCC).

METHODS

pRCC cases prospectively enrolled on the Children's Oncology Group study AREN03B2 underwent central pathology, radiology, surgery, and oncology review.

RESULTS

As of June 2012, 120 of a total of 3250 patients enrolled on AREN03B2 (3.7%) were found to have unilateral RCC (median age, 12.9 years [range, 1.9-22.1 years]; 52.5% were female). Central review classified these as translocation morphology (56 patients), papillary (20 patients), renal medullary carcinoma (13 patients), chromophobe (4 patients), oncocytoma (1 patient), conventional clear cell (1 patient), and RCC not otherwise specified (25 patients). Lymph node (LN) involvement (N+) was found in 35 of 73 cases (47.9%) for which LNs were sampled, including 19 of 40 cases with primary tumors measuring <7 cm (47.5%). Using a size cutoff of 1 cm, imaging detection of LN involvement had a sensitivity of 57.14% (20 of 35 cases; 95% CI, 39.35%-73.68%) and a specificity of 94.59% (35 of 37 cases; 95% CI, 81.81%-99.34%). Distant metastases were present in 23 cases (19.2%). Initial surgery was radical nephrectomy in 88 patients (73.3%), nephron-sparing surgery in 18 patients (15.0%), and biopsy in 14 patients (11.7%). Compared with patients undergoing radical nephrectomy, those treated with nephron-sparing surgery were less likely to have LNs sampled (6 of 18 patients [33.3%] vs 65 of 88 patients [73.9%]; P = .002).

CONCLUSIONS

Translocation RCC is the most common form of pediatric and adolescent RCC. Lymph node disease is common and observed among patients with small primary tumors. Imaging has a high specificity but relatively low sensitivity for the detection of such lymph node disease. Failure to sample LNs results in incomplete staging and potentially inadequate disease control for younger patients with RCC.

Xp 11.2 translocation renal carcinoma in young adults; recently classified distinct subtype

Background

XP11.2 renal translocation carcinomas are often encountered in paediatric group of patients where they are believed to be rather indolent. They are rare but more aggressive in young adults. They are slow growing, sometimes without characteristic symptoms and their biologic behaviour is uncertain.

Case report

We report two cases of this type of tumour in Slovenian young adult males with long and unusual history. Tumours were confirmed imunohistologically by positive reaction for CD10, P504S and TFE3.

Conclusions

According to the indications in the literature prognosis of these tumours in young adults depends upon the stage. It seems that cysts, haematomas and necrosis around the kidney are often encountered in these tumours. In advanced stage with lymph nodes involvement or distant metastases, the prognosis is poor. Surgery seems to be basic mode of therapy.

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.