No abstract

Juvenile idiopathic arthritis (JIA) is the most common cause of arthritis in children. It is characterized by inflammatory cell infiltration of synovial membranes leading to synovitis and synovial membrane thickening. Synovial chondromatosis is rare sequela of synovitis in which foci of cartilage develop within the synovial membrane of a joint capsule. We report a case of a 35-month old boy who developed tumefactive synovial hypertrophy and hyperplasia that mimicked synovial chondromatosis on MRI. The reactive synovium was arthroscopically excised and the patient's arthritis improved. Tumefactive synovial hypertrophy and hyperplasia mimicking synovial chondromatosis on MRI in the setting of JIA, has not been reported in this young of a patient in the literature to date. A discussion on imaging in oligoarticular JIA and synovial chondromatosis is presented herein.

Medial medullary syndrome (aka Dejerine syndrome) is a rare condition that develops following infarction of the medial medulla and is classically defined by the presence of Dejerine’s triad of contralateral weakness in upper and lower extremities, contralateral hemisensory loss of vibration and proprioception, and ipsilateral tongue weakness. It is typically caused by occlusion of the vertebral artery or one of its branches. We report the case of a 6-year-old girl who suffered a medial medullary infarction, and she was diagnosed with atypical Dejerine syndrome. Medial medullary infarct leading to atypical Dejerine syndrome has not been reported in this young of a patient in the literature to date.

Fibromatosis colli, also known as ‘sternocleidomastoid tumour of infancy’ or ‘pseudotumour of infancy’, is a rare condition involving fibrosis and swelling, or ‘tumour’ of the sternocleidomastoid muscle in newborns that typically occurs after a traumatic delivery. Although usually self-limited, fibromatosis colli can lead to congenital muscular torticollis and positional plagiocephaly due to uneven forces on the neonatal skull. Ultrasound is the diagnostic imaging modality of choice and can prevent additional imaging and unnecessary intervention.