Tuberous sclerosis complex: imaging the pieces of the puzzle

Radiol Bras. 2017 Jan/Fev;50(1):IX–X Tuberous sclerosis complex (TSC) is a genetic syndrome that predisposes to the formation of benign tumors, commonly known as hamartomas. It affects approximately 1 in 6,000 individuals, regardless of race or ethnicity. During the 1990s, more than 300 allelic variants of the TSC1 gene were reported, as were more than 1,000 allelic variants of the TSC2 gene. We now know that TSC can be inherited as an autosomal dominant disorder, although two thirds of all patients have de novo mutations. In an excellent pictorial essay published in this issue of Radiologia Brasileira, von Ranke et al. review the current clinical diagnostic criteria and the radiological features of multiorgan involvement in patients with tuberous sclerosis. The diagnosis of TSC is based on the demonstration of a mutation in the TSC1 or TSC2 genes. However, in up to 25% of patients with TSC, no such mutation is identified, and the disease is known to present as a heterogeneous genetic disorder with variable clinical expression. Regarding the difficulty of diagnosing TSC, the 2012 International Tuberous Sclerosis Complex Consensus Conference provided new recommendations that help standardize the approach to managing TSC, regardless of patient age or severity of the disease. The recommendations state that the involvement of multiple organ systems, at different stages in life, presents major difficulties in locating and identifying the expertise to comprehensively manage the medical care of individuals with TSC. In that scenario, a detailed evaluation of the brain, kidney, lung, skin, teeth, heart and eye are crucial, and for most of these, imaging plays an important role, not only in diagnosing and determining the extent of tuberous sclerosis but also in the treatment planning and patient follow-up. Given the recent improvements in knowledge of TSC, as well as the recent technological advances in imaging evaluation, the pictorial review conducted by von Ranke et al. offers an up-to-date and valuable aid in the presumptive diagnosis and determination of the extent of TSC, informing therapeutic decision-making. In their review, the most common manifestations of TSC were systematically organized and illustrated as intracranial, pulmonary, cardiac, renal, and other (such as skin and bone abnormalities). In recent decades, due to major advances in the field of cardiothoracic imaging, imaging features have come to be recog-