• ABSTRACT
    • A 10-year-old girl, with an intermittent fever for 15 days, visited our emergency department. Initial work-up revealed no signs of infection and no palpable abdominal mass. KUB showed only displaced bowel gas. Abdominal ultrasound was performed which disclosed a huge mass at the lower pole of the right kidney. Abdominal computed tomography (CT) confirmed a huge, heterogeneous mass arising from the right kidney and without involvement of regional lymph nodes and inferior vena cava. Radical nephrectomy was performed and Stage 2 renal cell carcinoma (RCC) was confirmed. Fever subsided spontaneously after operation. No local recurrence or distant metastasis was detected in the following 3 years. Thus, occult malignant neoplasm as infrequent as RCC should be in the list of differential diagnoses of fever of unknown origin (FUO). An abdominal ultrasound is a useful screening tool for early diagnosis of RCC.