CASE REPORT Primary Ewing's sarcoma of the kidney presenting with left-sided varicocele

Case Report A 24-year-old male presented with a left-sided scrotal lump of four years duration. Examination revealed a left-sided varicocele associated with an ill-defined mass in the left hypochondrium. On further questioning, the patient complained of left-sided intermittent flank pain, however, there were no significant urinary or systemic symptoms. Complete blood count, renal functions and erythrocyte sedimentation rate (ESR) were within normal ranges. Ultrasound scan showed a left-sided varicocele and a leftsided renal mass. Contrast-enhanced computed tomography (CECT) of the abdomen (Figure 1) revealed a left renal neoplasm compressing the vascular pedicle and para-aortic lymphadenopathy. The patient underwent left-sided radical nephrectomy. Left kidney, proximal ureter, left adrenal gland and an attached bowel mass containing distal ileum, caecum, large intestine and proximal sigmoid colon were removed during surgery.


Introduction
Ewing's sarcoma is a primary malignant bone tumour of neuroectodermal origin accounting for the second commonest paediatric bone sarcoma (1). However, its involvement of the urinary tract as primary renal neoplasms is extremely rare, representing less than 1% of renal tumours (2). We present a case of primary Ewing's sarcoma of the kidney presenting with left-sided varicocele.

Case Report
A 24-year-old male presented with a left-sided scrotal lump of four years duration. Examination revealed a left-sided varicocele associated with an ill-defined mass in the left hypochondrium. On further questioning, the patient complained of left-sided intermittent flank pain, however, there were no significant urinary or systemic symptoms. Complete blood count, renal functions and erythrocyte sedimentation rate (ESR) were within normal ranges. Ultrasound scan showed a left-sided varicocele and a leftsided renal mass. Contrast-enhanced computed tomography (CECT) of the abdomen ( Figure 1) revealed a left renal neoplasm compressing the vascular pedicle and para-aortic lymphadenopathy. The patient underwent left-sided radical nephrectomy. Left kidney, proximal ureter, left adrenal gland and an attached bowel mass containing distal ileum, caecum, large intestine and proximal sigmoid colon were removed during surgery.
Macroscopic examination revealed a mass measuring 150 x 95 x 90 mm mainly in the hilar region focally extending up to renal capsule and perinephric fat, replacing the normal renal parenchyma. Intestines were free of tumour invasion. Microscopy revealed a small round blue cell tumour with extensive necrotic area composed of solid sheets and nests of cells with hyperchromatic rounded to oval nuclei with scanty cytoplasm (Figure 2). Frequent mitotic figures, pseudorosette formation and microvascular invasion were seen. Adrenal gland showed tumour emboli within vessels. Peri hilar region did not reveal lymph nodes. On immunohistochemistry, the tumour was negative for leukocyte common antigen (LCA), terminal deoxynucleotidyl transferase (TdT), pancytokeratin, WT1, Desmin, chromogranin and cluster differentiation 56 (CD56) excluding the possibility of a lymphoma and Wilms tumour. Immune-morphological features were of an Ewing's sarcoma (Figure 3). After surgery  Ewing's Sarcoma is associated with translocations causing fusion of the EWS gene on 22q12 with a member of E26 Transformation Specific (ETS) family of transcription factors (1,2). These fusion genes can be detected by fluorescent insitu hybridization (FISH) techniques and are used as diagnostic markers in specialised centres.
Due to the rarity of this condition, specific treatment methods are not well established. Most of the cases are treated with radical nephrectomy with neoadjuvant and adjuvant chemoradiotherapy (5). Chemoradiotherapy has demonstrated significant survival benefits and improvement of symptoms even in patients with metastatic disease (1).
patient was referred to the National Cancer Institute for adjuvant chemoradiotherapy.

Discussion
Primary Ewing's sarcoma of the kidney is a rare entity associated with poor clinical outcomes (1). As in our case, it mainly affects young males at a median age of 28 years (1). Patients with primary renal Ewing's sarcomas commonly present with pain, haematuria and renal masses while a minority present with constitutional symptoms such as fatigue or loss of appetite (1,2). In a case series, one-third of patients had metastasis at the time of diagnosis and 40% developed metastasis shortly after surgery (2). Commonest metastatic sites were lung (60%), liver (37%) abdominal lymph nodes (20%) and bones (16%) (2).
CECT may show large masses with necrotic, haemorrhagic and occasionally calcified areas but fails to provide any specific signs (  Learning Points: Ÿ Primary Ewing's Sarcoma of the kidney is a very rare entity.
Ÿ It commonly affects young males.
Ÿ Diagnosis is primarily by histological, immunohistochemical stains and genetic testing.
Ÿ Nephrectomy with neoadjuvant and adjuvant chemoradiotherapy is the preferred method of treatment.