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.