Even if CT scan is the gold standard to characterize a renal mass, sometimes it can be misleading, showing a solid renal mass as a cystic one. Tubulocystic renal cell carcinoma (TcRCC) is a rare and recently discovered RCC variant which radiologically may demonstrate as Bosniak type II to IV, even if it has solid features. We describe a case of a patient with left kidney TcRCC initially diagnosed as a renal cyst, who finally underwent radical nephrectomy showing a large, solid neoplasm. Due to its unusual CT appearance, TcRCC can be confused with cystic lesions and several other benign or malignant entities. Ultrasound can be a useful aid for the characterization of these renal tumours.