A primary Ewing’s sarcoma of the kidney: A case report and review of literature

Abstract

Primary Ewing’s kidney sarcoma is a rare and aggressive cancer with poor treatment outcomes. Furthermore, clinical presentations are nonspecific, such as abdominal pain, abdominal mass, cachexia, or hematuria. Currently, there is no consensus guideline for the treatment of this condition. We report on a 22-year-old man who presented with gross hematuria for 3 weeks. Computed tomography demonstrated a huge right renal mass with a thrombus in the inferior vena cava (IVC) without visceral metastasis. A percutaneous tissue biopsy revealed Ewing’s sarcoma (ES) and the patient received neoadjuvant chemotherapy (doxorubicin and ifosfamide) for four cycles. This reduced the tumor’s size significantly and made it eligible for surgical intervention. Radical nephrectomy and tumor thrombus removal with wedge IVC wall were performed. The final diagnosis of ES was confirmed by the immunohistochemistry of the kidney specimen. After a 5-year follow-up of the patient, clinical and imaging evidence demonstrated that there was no disease recurrence.

INTRODUCTION

The Ewing’s sarcoma family of tumors includes Ewing’s sarcoma (ES), primitive neuroectodermal tumor (PNET), and Askin’s tumor.[1] These tumors originate from neuroectoderm. They are a poorly differentiated group and are aggressive. ES is usually located in bone, soft tissue, and the chest wall, especially in children and young adults.[2,3] Primary ES in the kidney is extremely rare. Most patients have a poor prognosis with rapid clinical progression.[4] The first report of ES/PNET in the kidney was published in 1975,[5] and there have only been 100 cases reported after this.[6] In an earlier report, due to its aggressiveness, complete surgical resection only achieved 24%.[7] Currently, multidisciplinary teams are involved in the treatment strategy for this condition. The treatment includes neoadjuvant chemotherapy, local control with surgery, or radiation with additional postoperative chemotherapy.[1] A large meta-analysis demonstrated a 5-year disease-free survival of 45%–55%.[8] We report on the case of a 22-year-old man with ES of the right kidney with inferior vena cava (IVC) involvement, which was completely removed by surgical intervention.

CASE REPORT

A Thai 22-year old visited the outpatient unit of our university hospital due to gross hematuria for 3 weeks. He did not complain of abdominal pain, flank pain, fever, nausea, vomiting, or weight loss. He was a 3^rd-year engineering college student. He denied the presence of underlying disease or any current medication used. An initial evaluation with multiphase computed tomography (CT) revealed a 14.4 cm × 14.3 cm × 9.7 cm heterogeneous enhancing mass at the right kidney. The mass extended along the right hepatic vein, intrahepatic and hepatic IVC without intraabdominal metastasis [Figure 1]. A chest CT did not identify any pulmonary nodules or masses. Initial laboratory testing revealed a hematocrit level of 36%, too numerous to count red blood cells in urine analysis and an estimated glomerular filtration rate of 106 ml/min/1.73 m².

Figure 1.

A contrast-enhanced CT of the abdomen revealed a large right renal mass with IVC involvement. CT: Computed tomography, IVC: Inferior vena cava

The patient was referred to a multidisciplinary team. Although the presentation and imaging favor a diagnosis of renal cell carcinoma (RCC), rare types of renal cancer were also included in the differential diagnosis due to the extremely young age of the patient and we decided to wait for the tissue pathology report before commencing treatment. A percutaneous biopsy renal mass was performed and pathologic testing yielded that the patient was suffering from ES, and CD99 expression was found by immunostaining. The patient received neoadjuvant treatment of four cycles of doxorubicin and ifosfamide as neoadjuvant treatment. During the chemotherapy period, there were no serious side effects. CT after neoadjuvant treatment revealed significant improvement of the right renal mass and thrombus in IVC [Figure 2]. The patient underwent open radical nephrectomy and tumor thrombus removal with wedge IVC wall and bovine pericardial patch; blood loss was 3000 mL. The pathologic analysis result was that there was “no viable tumor.” The label specimen for tumor thrombus revealed old hemorrhage. The patient was hospitalized for a total of 12 days. He was discharged without major complications.

Figure 2.

The contrast-enhanced CT of the abdomen after neoadjuvant chemotherapy. Right renal mass and tumor thrombus in IVC were significantly reduced in size. CT: Computed tomography, IVC: Inferior vena cava

Magnetic resonance imaging was performed 3 months after the procedure. There was no evidence of tumor recurrence at the right renal fossa and no evidence of visceral metastases. The patient was given appointments for biannual follow-ups also incorporating imaging. After a 5-year follow-up, clinical and imaging evidence demonstrated that there was no disease recurrence.

DISCUSSION

ES of the kidney may be a result of embryonic neural crest cells migrating into the kidney and undergoing tumorigenesis there. ES usually occurs in young adults and the most common site of extraskeletal ES tumor is the trunk but the kidneys and retroperitoneum are also potential locations. Most patients have a delayed diagnosis and commonly present with a large abdominal mass due to the location of the tumor.[9] Although vascular tumor thrombus is often viewed as a unique feature of clear cell RCC; approximately 50% of ES patients also present with tumor thrombus.[10] Metastatic disease is very common in ES of the kidney. The most common sites of metastasis were the lung, liver, lymph nodes, and bones.[6] Nearly, 40% of ES of the kidney had overt metastatic disease. Despite reports that vascular thrombus is strongly related to pulmonary metastasis,[11] there was no such indication in chest tomography, neither were there any signs of visceral metastasis in regard to the patient in this report. Unlike cytoreductive nephrectomy in RCC, a pretreatment percutaneous biopsy can provide essential information for ES, especially in regard to metastasis. In addition, successful surgical local control depends on tumor’s response to upfront chemotherapy.[11] Currently, the standard treatment of ES was nephrectomy with neoadjuvant and adjuvant treatment.[6,7,11] Chemotherapy possibly reduces the size of the tumor and can be a potential cure for some patients.[12,13] Our patient received neoadjuvant therapy, followed up with radical nephrectomy. The histology of conventional or classical ES was constituted by a diffuse and monotonous proliferation of homogeneous small round blue cells in hematoxylin and eosin. The hallmarks of immunohistochemistry of ES are CD99 and caveolin-1 expression.[14] In molecular studies, it is characterized by translocations and fusions of the EWSR1 gene with an ETS family gene.[8,11,15] Unfortunately, we did not perform a molecular study. The 5-year overall survival of localized disease and metastatic disease is 61 months and 14 months, respectively.[16]

In conclusion, ES of the kidney is a rare and aggressive condition. Most patients present with a large abdominal mass and have poor survival, especially in regard to overt metastatic disease. Tissue biopsy and neoadjuvant chemotherapy could be a treatment of choice. Although there is a high mortality rate, multimodality treatments by multidisciplinary teams can improve survival outcomes.

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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.