Multilevel bilateral calcified thoracic spinal synovial cysts.

Synovial cysts of the thoracic spine are quite rare. Bilateral presentation is even less frequent, and to the authors' knowledge multilevel occurrence and consistent calcification have not been reported so far. The pathogenesis of these cysts is unknown and their histological features have not been studied. They may be overlooked as the cause of myelopathy. The authors report a series of 4 cases of bilateral, multilevel, consistently calcified thoracic synovial cysts. The details of clinical, radiological, and histological findings are presented, along with a review of the literature, and a hypothesis on the pathogenesis of these lesions is formulated based on results of the clinical and pathological studies performed in these patients.