Clear cell sarcoma of the kidney in children: experience in a developing country

Outcomes of children with clear cell sarcoma of kidney following NWTS strategies in Shanghai China (2003-2021)

BACKGROUND

Although clear cell sarcoma of kidney (CCSK) is rare, it is the second most common renal tumor in children after Wilms' tumor. NWTS and SIOP are two major groups which had made tremendous efforts on renal tumors, but the strategies are different, for NWTS follows the upfront surgery principle providing definite pathology and the SIOP follows the upfront chemotherapy principle, each has its own advantages. Here we aimed to evaluate the outcomes of CCSK in China following NWTS strategies to analyze the prognostic factors.

METHODS

For this multicenter retrospective study, a total of 54 patients were enrolled from three children's hospitals, between April 2003 and December 2021. Treatment comprised upfront radical nephrectomy, followed by radiotherapy and intensive chemotherapy. Clinical records were regularly updated. Prognostic factors and survival rates were evaluated.

RESULTS

The 54 enrolled patients had a median age of 37 months (range, 4 months to 11.4 years). The stage distribution was 16% stage I (n = 9), 30% stage II (n = 16), 39% stage III (n = 21), and 15% stage IV (n = 8). Among stage IV, metastasis sites included the lung (n = 6), bone (n = 1), and intra-orbital/cervical lymph node (n = 1). After a median follow-up of 5.6 years, the 5-year event-free survival (EFS) was 82.4±5.4%, and overall survival was 88.1±4.6%. The EFS was 100% for stage I, 93.8 ±6.1% for stage II, 71.1±10.0% for stage III, and 68.6±18.6% for stage IV. Univariate analysis revealed that staging (III/IV), tumor rupture, and inferior vena cava tumor thrombus were inferior prognostic factors. Multivariate analysis revealed that tumor rupture was independent poor prognostic factor (P = 0.01, HR 5.9). Among relapsed patients, relapse occurred a median of 11 months after diagnosis (range, 4-41 months), and 50% (4/8) achieved a second complete remission after multiple treatment. None of the six lung metastasis patients received lung RT, only one patient developed a relapse and was salvaged by RT after relapse.

CONCLUSIONS

Tumor rupture was independent poor prognostic factor. Upfront surgery of NWTS strategies can make a definite pathology diagnosis, but how to reduce tumor rupture during surgery is important especially in developing countries. The outcomes of patients with stage I-III CCSK in China were comparable to findings in other developed countries. Better outcomes were achieved in stage IV CCSK by using an intensive chemotherapy regimen including carboplatin, which require further confirmation by AREN0321. Lung RT may be safely omitted in selected patients who achieve a compete radiographic response after 6 weeks of systemic treatment (including surgery). Treatment should be encouraged even in CCSK cases with metastasis and relapse.

Clear cell sarcoma of the kidney with inferior vena cava thrombus: a case report

BACKGROUND

Clear cell sarcoma of the kidney is an uncommon pediatric renal malignant neoplasm that is typically characterized in 2-3-year-olds by aggressive behavior and late relapses. Our literature review revealed fewer than ten previously reported cases of CCSK with inferior vena cava thrombus, with only five in the pediatric age group.

CASE PRESENTATION

We report the case of a 14-year-old Syrian girl who complained of mild pain in the left lumbar region pain with hematuria. On physical examination, a mass was palpated in the left flank. Abdominal ultrasonography revealed a left renal mass (7 × 5 × 2 cm³), associated with dilatation of the left renal vein. Contrast abdominal computed tomography showed a mass measuring 7 × 5 × 3 cm³ with the presence of thrombus extending into the inferior cavity down to the right atrium that was initially diagnosed as Wilms' tumor. Radical right nephrectomy with excision of the thrombus was undertaken. Histological immunostaining revealed a diagnosis of the tumor as clear cell sarcoma with vascular tumor thrombus extending to the inferior vena cava.

CONCLUSION

Clear cell sarcoma and Wilms' tumor are similar in terms of typical age of appearance, clinical features, and histopathology, but with different methods of treatment and prognosis. The differential diagnosis of such masses is thus very important. We present the case of a patient with clear cell sarcoma with unusual age, with complete removal of the thromboses in the inferior vena cava and the right atrium.

Incidence patterns of childhood non-Wilms renal tumors: Comparing data of the Nationwide Registry of Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST), Greece, and the Surveillance, Epidemiology, and End Results Program (SEER), USA

BACKGROUND

We used, for the first time, data registered in the Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST)-Greece to estimate incidence/time trends of the rare childhood (0-14 years) non-Wilms tumors (non-WT), and compared the results of malignant non-WT to those from the Surveillance, Epidemiology, and End Results Program (SEER)-USA.

METHODS

Fifty-five cases (n = 33 malignant-only) were extracted from NARECHEM-ST (2001-2020) and 332 malignant cases from SEER (1990-2017). To allow between-country comparisons, age-standardized incidence rates (AIR) of malignant-only non-WT were calculated, and temporal trends were evaluated using Poisson and joinpoint regressions.

RESULTS

In NARECHEM-ST, malignant and non-malignant non-WT accounted for 22.6% of all renal tumors. Among malignant tumors, the AIR was 1.0/106 children in Greece, similar to that calculated for SEER, USA (AIR=0.9/106). The proportion of infant malignant and non-malignant non-WT was 27% (20% before 6 months) in NARECHEM-ST. Most common non-WT in Greece were congenital mesoblastic nephromas (CMN) diagnosed mainly in infancy (CIR=7.2/106). The proportion of infant malignant non-WT was 20% in SEER (AIRinfancy=2.5/106), mainly attributed to rhabdoid tumors (CIR=1.6/106). The male-to-female (M:F) ratio of malignant non-WT was 0.9 in NARECHEM-ST vs. 1.2 in SEER, whereas boys outnumbered girls with clear cell sarcoma in NARECHEM-ST (M:F=4.0). Lastly, significantly increasing trends in incidence rates were noted in NARECHEM-ST [+ 6.8%, 95% confidence intervals (CI): 0.5, 13.3] and in SEER (+7.3%, 95%CI: 5.6, 9.0).

CONCLUSIONS

Observed incidence, time trends and sociodemographic variations of non-WT may reflect differential registration practices and healthcare delivery patterns including differences regarding surveillance, coding and treatment practices.

Imaging features and differences among the three primary malignant non-Wilms tumors in children

Background

The pathology, treatment and prognosis of malignant non-Wilms tumors (NWTs) are different, so it is necessary to differentiate these types of tumors. The purpose of this study was to review the clinical and imaging features of malignant NWTs and features of tumor metastasis.

Methods

We retrospectively analyzed the CT images of 65 pediatric patients with NWTs from March 2008 to July 2020, mainly including clear cell sarcoma of the kidney (CCSK), malignant rhabdomyoma tumor of the kidney (MRTK) and renal cell carcinoma (RCC). Available pretreatment contrast-enhanced abdominal CT examinations were reviewed. The clinical features of the patients, imaging findings of the primary mass, and locoregional metastasis patterns were evaluated in correlation with pathological and surgical findings.

Results

The study included CCSK (22 cases), MRTK (27 cases) and RCC (16 cases). There were no significant differences observed among the sex ratios of CCSK, MRTK and RCC (all P > 0.05). Among the three tumors, the onset age of MRTK patients was the smallest, while that of RCC patients was the largest (all P < 0.05). The tumor diameter of CCSK was larger than that of MRTK and RCC (all P < 0.001). For hemorrhage and necrosis, the proportion of MRTK patients was larger than that of the other two tumors (P = 0.017). For calcification in tumors, the proportion of calcification in RCC was highest (P = 0.009). Only MRTK showed subcapsular fluid (P < 0.001). In the arterial phase, the proportion of slight enhancement in RCC was lower than that in the other two tumors (P = 0.007), and the proportion of marked enhancement was the highest (P = 0.002). In the venous phase, the proportion of slight enhancement in RCC was lower than that in the other two tumors (P < 0.001). Only CCSK had bone metastasis. There was no liver and lung metastasis in RCC.

Conclusions

NWTs have their own imaging and clinical manifestations. CCSK can cause vertebral metastasis, MRTK can cause subcapsular effusion, and RCC tumor density is usually high and calcification. These diagnostic points can play a role in clinical diagnosis.

Retrospective analysis of outcomes in patients with clear cell sarcoma of the kidney: A tertiary single-institution experience

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) is a rare and aggressive tumor. This study aims to describe the clinical characteristics and outcomes of CCSK patients in one of the largest pediatric medical centers in China.

METHODS

We included all patients diagnosed with CCSK between January 2008 and March 2019 at the Children's Hospital of Chongqing Medical University, China. The patients' demographics, clinical presentation, and management were reviewed. Follow-up was continued until December 2019.

RESULTS

In total, 41 CCSK patients (66% male) with a median age of 24 months (range 3-108 months) were identified. The stage distributions of stages I, II, III and IV were 42%, 34%, 24% and 0%, respectively. Preoperative chemotherapy was administered to 7/41 patients. All patients underwent radical nephrectomy and postoperative chemotherapy. The median number of lymph nodes sampled was 4 (range 1-12). Radiotherapy was applied in 8/41 patients. The 5-year event-free survival (EFS) and overall survival (OS) were 63.9% and 78.8%, respectively. Of the 41 patients, 11 patients experienced relapse at a median time of 19 months (range 5-72 months). The most common site of recurrence was the tumor bed (9/11). Young age was a significant adverse prognostic factor for EFS.

CONCLUSIONS

The overall outcome of CCSK patients in our hospital is poorer than that in developed regions. More research is needed to clarify the underlying causes of poorer outcomes in young patients and improve outcomes.

TYPE OF STUDY

Retrospective study.

LEVEL OF EVIDENCE

LEVEL IV.

Incidence, treatment, and outcomes of primary and recurrent Non-Wilms renal tumors in children: Report of 109 patients treated at a single institution

INTRODUCTION

Non-Wilms renal tumors represent a compelling subset of childhood renal tumors. However, their relative rarity renders accurate diagnosis, and therapy challenging which in some instance is inferred from their adult counterparts.

OBJECTIVE

To describe the incidence and analyze the diagnostic challenges, therapies and, outcomes of non-Wilms renal tumors at the largest tertiary cancer centre in India.

METHODS

All patients with histologically confirmed non-Wilms renal tumours diagnosed in the paediatric oncology unit of Tata Memorial Hospital between 2006 and 2019 were included. Data regarding clinical and radiological features and treatment outcomes were retrieved from the prospectively maintained institutional database. At the outset, histological types were categorised into a high and low-risk group depending on anticipated survival. Survival analysis was performed utilising the Kaplan-Meier method on SPSS software version 24.0.

RESULTS

Of the 569 patients with renal tumors, 109 (19%) patients with primary (n = 97) or recurrent (n = 12) non-Wilms renal tumors were included. Histological high-risk group included clear cell sarcoma (CCSK) (39.4%), renal cell carcinoma (RCC) (19.3%), malignant rhabdoid tumor (MRTK) (12.8%), Ewing's sarcoma (rES) (15.6%), synovial sarcoma (2%), and undifferentiated sarcoma (2%). The low-risk group comprised of congenital mesoblastic nephroma (CMN) (4.6%), cystic partially differentiated nephroblastoma (2%), and other rare tumors (3%). Diagnostic error occurred in 2 patients in the high-risk group. All low-risk tumours were treated with surgery alone and most (97%) high-risk tumors were operated either upfront (61.5%) or after preoperative chemotherapy (38.4%). Adjuvant therapy based on histology was offered to 70%. The recurrent tumors received various salvage treatments including chemotherapy; radiotherapy; surgery and immunotherapy, however, only 2 patients could be salvaged. The 3-year overall survival for the entire cohort with primary tumors was 59%, and the survival rates were 76.7%, 77.9%, 0.0%, and 52% for CCSK, RCC, MRTK, and rES (summary figure). Low-risk tumors had 100% survival while the recurrent tumors had a median survival of 10.5 months.

CONCLUSIONS

Non-Wilms renal tumors constitute a heterogeneous group of tumors, accounting for less than 20% of all renal tumors. Low-risk tumors are associated with excellent outcomes following surgery alone while the high-risk tumours have a variable outcome. MRTK and recurrent non-Wilms tumour have the worst survival. Favourable outcomes for CCSK and RCC and worst outcomes for MRTK were observed in this study. Renal ES have higher incidence of treatment failure and unsatisfactory outcomes. Recurrent non-Wilms tumours have an extremely poor outcome and more alternative or innovative approaches are needed for their treatment.

Renal clear cell sarcoma presenting as a spontaneous renal hematoma: A rare presentation

Clear cell sarcoma of the kidney (CCSK) is an uncommon renal neoplasm of childhood. It represents between 2% and 9% of all pediatric renal tumors, and generally arises before the age of 5 years. It often mimics other pediatric renal tumors. Presently described is the case of a 7-year-old girl who presented with complaints of vomiting and abdominal pain. Abdominal ultrasonography revealed a right renal mass, and the patient developed a renal hematoma a few hours after admission. The patient underwent a nephroureterectomy with a provisional diagnosis of Wilms tumor; however, histopathological examination of a specimen revealed CCSK. CCSK is similar to Wilms tumor in terms of the typical age of appearance and clinical and histopathological features, but the treatment method and prognosis are different. Therefore, the differential diagnosis is very important. This case was presented to draw attention to a rare presentation of clear cell sarcoma. CCSK should be kept in mind in the differential diagnosis of a renal mass.

Bilateral clear cell sarcoma of the kidney

Clear cell sarcoma of the kidney (CCSK) accounts for 2-5% of all pediatric renal malignancies, and is known for its propensity to metastasize to bone and other sites. We are reporting two cases with bilateral CCSK that were diagnosed at our institution. One patient initially presented with bilateral renal masses, as well as pulmonary, hepatic and bone metastasis; while other present only with bilateral masses with no evident distant metastasis. Both patients received aggressive neo-adjuvant chemotherapy to decrease tumor size. One patient completed his designated treatment and initially showed complete remission (CR); eventually suffering from relapse. The other patient's tumor progressed during the course of chemotherapy. Both cases manifested brain dissemination at the time of relapse or progression. This emphasizes the importance of staging stratification in CCSK. This also illustrates CCSK's ability to metastasize to bone and other sites including the brain (a primary relapse site in our cases).

Clear cell sarcoma of the kidney: patients' characteristics and improved outcome in developing countries

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) is a rare and aggressive tumor accounting for 5% of pediatric renal tumors with an incidence of 20 patients per year in the USA. It is bone metastasizing with poor prognosis. Our aim was to show characteristics of patients in relation to improved outcome in one of the developing countries.

PROCEDURE

We included all patients diagnosed as CCSK in the period between July 2007 and March 2012 at Children's Cancer Hospital, Egypt. Patients' demographics, clinical presentation, pathology, and management were reviewed. Follow up was continued until April 2013.

RESULTS

Twenty-five patients were identified in the defined time interval, accounting for 7% all renal tumors diagnosed at the hospital. Mean age was 36 months. Abdominal swelling and hematuria were the most common presentations. Stages I, II, III, IV, and V represented 9 (36%), 3 (12%), 8 (32%), 3 (12%), and 2 (8%), respectively. Twenty-four patients had radical nephrectomy either upfront or after neo-adjuvant chemotherapy. Surgery was followed by adjuvant chemotherapy. Abdominal radiotherapy was given for local stages II and III. Twenty-two patients reached complete remission, while one patient had stationary disease and two patients died due to progression and relapse. Overall survival was 88.5% and event-free survival was 87.8% at 45 months.

CONCLUSION

Although previous studies indicate poor prognosis of CCSK, our experience shows that those patients can be treated using extensive chemotherapy combined with proper local control.

Malignant renal tumors in childhood: report of 54 cases treated at a single institution

BACKGROUND

Wilms tumor is the most common primary renal malignancy occurring in childhood. Significant improvement has been made in the treatment of children with Wilms tumor. However, the treatment of patients with non-Wilms renal tumors remains challenging.

METHODS

Between 1991 and 2010, 70 children with renal tumors were diagnosed at a single institution. Fifty-four patients were histologically confirmed and divided into three groups, including 42 Wilms tumors, seven clear cell sarcomas of kidney, and five malignant rhabdoid tumors. Most patients underwent unilateral nephrectomy and lymph node sampling followed by adjuvant chemotherapy. Twenty-one of these patients subsequently received radiotherapy.

RESULTS

During follow-up, 12 patients died of progressive disease and one died of operative mortality. One patient with unilateral pleural metastases subsequently underwent hematopoietic stem cell transplantation. The median survival time of all patients was 88 months. Children under 2 years of age at diagnosis with Wilms tumor or clear cell sarcoma of kidney had an excellent survival rate of 100% compared to the 0% survival rate of MRT.

CONCLUSION

Younger age at diagnosis bore a better prognosis than did older age, whereas a diagnosis of malignant rhabdoid tumor portended a worse prognosis. Younger patients and appropriate treatment may have contributed to the improved prognosis of clear cell sarcoma of kidney.

Incidental capture of rarely diagnosed pediatric tumor: an infant boy with clear cell sarcoma of the kidney

Clear cell sarcoma of the kidney (CCSK) is an uncommon neoplasm that accounts for less than 5% of all pediatric renal tumors. Compared with Wilms' tumor, CCSK has a higher rate of relapse, greater propensity for bone metastasis, and poorer overall survival. We present the case of a 19-month-old boy with a large renal mass diagnosed incidentally by ultrasonography during surveillance for vesicoureteral reflux. This report describes the rare occurrence of an incidental radiologic capture of CCSK and provides a brief review of disease pathology.

Clear cell sarcoma of the kidney misdiagnosed as mesoblastic nephroma: a case report and review of the literature

Clear cell sarcoma of the kidney (CCSK) is a rare renal neoplasm of paediatrics, making up about 3% of all renal tumours in paediatrics, with a high tendency for developing bone metastasis. A seven year-old boy was referred to our clinic with two firm, large masses over the manubrium of the sternum and right frontal area, which pathologically were confirmed as a metastatic CCSK. The patient had a history of a renal mass three years earlier, for which radical nephrectomy had been performed, and histopathologic diagnosis was compatible with mesoblastic nephroma. Thus, no further investigation and therapy had been applied for the patient. CCSK is a rare but malignant and aggressive paediatric renal tumour, with a high tendency for developing distant bone metastases, leading to its poor prognosis. CCSK could be misdiagnosed as several other renal tumours such as mesoblastic nephroma, and thus CCSK should be taken carefully into consideration in the diagnosis of renal tumours.

The results of treatment of children with metastatic Wilms tumours (WT) in an African setting: do liver metastases have a negative impact on survival?

BACKGROUND

From Africa, where socio-economic circumstances differ from the developed world, there are no data regarding the influence of liver metastases on survival of children with Wilms tumour.

PROCEDURE

One hundred fifty new patients with WT were seen between 2002 and 2010, 45 (30%) had metastases at diagnosis. Seven patients had bilateral disease with additional visceral metastases. Nine patients who developed liver metastases during treatment were excluded. The site of metastases and the results of pretreatment biopsies were retrieved. Neo-adjuvant chemotherapy was combined with nutritional resuscitation, and aggressive supportive care. Post-operative treatment was determined by stage and histology.

RESULTS

Liver metastases were present in 19 (42%) patients but were the sole metastatic site in only 4 (9%). Overall survival at 5 years was 58.5%. Event Free Survival was 54%. Thirty-three (73%) had favourable histology, nine unfavourable and undetermined in three. No influence of histology on outcome was evident. Three patients had resection of persistent liver metastases. The pattern of metastatic disease had no influence on outcome. Despite aggressive supportive care two patients (4%) died within a week of presentation. Two patients died of chemotoxicity and two of complications following biopsy. Eight patients (17%) were lost to follow-up of whom five were on palliative treatment only.

CONCLUSIONS

In Africa liver metastases do not appear to worsen the prognosis of children with Stage IV WT. Despite the poor socio-economic circumstances survival is comparable to other countries.

Pediatric non-Wilms' renal tumors: a third world experience

BACKGROUND

Pediatric non-Wilms' renal tumors (NWRT) are poorly understood owing to their heterogeneity and relative rarity. This study aimed at auditing the outcome of the management of NWRT in a tertiary hospital in the Third World.

METHODS

Records of all patients (n = 68) treated for NWRT over a 32-year period (1978-2010) were reviewed retrospectively.

RESULTS

The major histological groups included clear cell sarcoma of the kidney (CCSK) (33.8%), mesoblastic nephroma (17.6%), cystic partially differentiated nephroblastoma (CPDN) (17.6%), intrarenal neuroblastoma (8.8%), malignant rhabdoid tumor (MRT) (7.4%), and renal cell carcinoma (RCC) (5.9%). Sixteen (69.7%) patients with CCSK and 11 (91.7%) with CPDN were aged 1-4 years. Ten (83.3%) patients with mesoblastic nephroma were aged <1 year and three (60.0%) with RCC were aged 10-14 years. Ten (43.5%) patients with CCSK and four (80.0%) with RCC had metastases at diagnosis. The sensitivity of a pretreatment Tru-Cut biopsy was 100% for MRT. All the patients with CCSK, mesoblastic nephroma, CPDN, and RCC had radical nephrectomy. Only eight (34.8%) patients with CCSK received radiotherapy. The overall 1-10-year survival rates were 52.2%, 91.7%, 75.0%, 40.0% and 0.0% for CCSK, mesoblastic nephroma, CPDN, RCC, and MRT, respectively. The overall 1-10-year survival for the entire cohort was 51.5%.

CONCLUSIONS

The demography and clinical presentation of pediatric NWRT, which comprises 13.6% of pediatric renal tumors in the Third World, were similar to those in the Developed World. The overall 1-10-year survival for pediatric NWRT was low.

Clear cell sarcoma of the kidney: a review

Clear cell sarcoma of the kidney (CCSK) is a rare renal tumour that is observed most often in children under 3years of age. Only a few large series of CCSK have been reported and patients with CCSK are often included among patients with other types of childhood renal tumours. The purpose of this paper is to review the published series and case reports of CCSK and to create an up-to-date overview of clinical and histological features, genetics, treatment, and outcome.

A case of clear cell sarcoma of the kidney

Clear cell renal sarcoma is a rare tumor and comprises 4% of primary pediatric malignant renal tumors. It is known as an aggressive tumor with poor prognosis. Clinically and radiographically, it resembles Wilms tumor. We present a case of a child with an abdominal mass that was diagnosed as clear cell sarcoma of her right kidney.