MRI features of joint capsule-originating hamartomas in a pediatric patient with tuberous sclerosis: a novel case report

Hamartomas are well-recognized benign growths associated with tuberous sclerosis complex (TSC), occurring frequently in the skin, central nervous system, and kidneys. Although musculoskeletal manifestations have been documented, intra-articular hamartomas originating specifically from the joint capsule have not been previously reported to the best of our knowledge. We present a unique case involving a 9-year-old female with genetically confirmed TSC who exhibited multiple intra-articular hamartomatous lesions originating from the joint capsules of the hip and knee. These lesions were distinctly visible on magnetic resonance imaging (MRI), displaying signal characteristics consistent with hamartomas, and they were confirmed by histopathological analysis. This underscores the importance of considering capsular hamartomas in the differential diagnosis of intra-articular masses in TSC and highlights the diagnostic value of MRI in identifying such rare manifestations.