Clear cell sarcoma of the kidney in childhood

Purpose: To demonstrate clear sarcoma of the kidney (CCSK) imaging diagnosis in an infant hospital, its incidence in childhood and its correlation to the prevalent malignant renal pathology. Material and methods: We retrospectively reviewed 12 patients with histological CCSK diagnosis, examined in our hospital from July 1987 to May 2000. We analysed the clinical findings, we used diagnostic methods and histopathological characteristics, and assessed clinical and radiographic aspects and its differences with Wilms tumour. Results: There was higher incidence in males (4:1). Patient's age ranged from 15 moths to 14 years. All patients had a palpable abdominal mass. Arterial hypertension and hematuria was present in 25% and 16% of the cases. In 6 patients the renal tumour exceeded the middle abdominal line. Ultrasonography revealed: unilateral heterogeneous mass, with hypoechoic areas (necrosis), cystic appearance was identified in 2 cases, calcifications in 2 cases and 1 case showed inferior vena cava thrombosis. Two patients already showed lung metastases at the time of admittance in our institution. Computed Tomography (CT) supported sonographic findings. During clinical evolution metastases were confirmed in 8 patients (bone, lung and testicles) and local relapse in one. Conclusion: CCKS represented 0.5% of renal malignant tumours treated in our hospital and diagnosis was only achieved through pathological anatomy, since no clinical-radiographic sign is pathognomonic to allow a distinction from Wilms tumour. Despite its low incidence, this malignant neoplasm should be considered in differential diagnosis. (author)