Intra-articular synovial arteriovenous malformation: A case report study

Synovial arteriovenous malformation (SAVM) of the knee is an exceedingly rare vascular anomaly, often presenting a diagnostic challenge in pediatric populations due to its nonspecific symptoms of chronic pain and recurrent swelling. We present the case of a 10-year-old boy with a 15-month history of intermittent right knee pain and difficulty bearing weight, despite normal initial radiographs. Advanced multiplanar MRI revealed an ill-defined intra-articular lesion within Hoffa's fat pad. The imaging features was not specific, and the differential diagnosis include AVM and Tenosynovial Giant Cell Tumor (TGCT). Following surgical excision, histopathological evaluation confirmed a synovial arteriovenous malformation. This case emphasizes that while SAVM mimics common conditions like juvenile idiopathic arthritis or TGCT.