Imaging description

A 14-year-old girl presented with seizures. The clinical examination revealed wart-like, small 4–5 mm, brownish nodules of the face with a bimalar distribution as well as palpable flank masses bilaterally. An ultrasound of the kidneys demonstrated multiple renal cysts bilaterally (Fig. 57.1a). Color Doppler evaluation did not reveal any vascular abnormality (Fig. 57.1a). A CT confirmed the cystic nature of the renal lesions (Fig. 57.1b); there was no evidence for solid renal masses. Tuberous sclerosis was suggested as the most likely diagnosis.

Criteria for uncomplicated renal cysts on ultrasound scans include the presence of an anechoic, round or oval structure with sharply circumscribed smooth walls and enhanced through-transmission. On CT scans, criteria for a cyst include a round or oval well-defined lesion with water attenuation, sharply circumscribed smooth walls, and lack of enhancement or fat attenuation. On MR images, a cyst is defined as a lesion that demonstrates fluid signal intensity on T1- (dark) and T2- (bright) weighted images, with round, well-defined borders and sharply circumscribed smooth walls, and no contrast enhancement.