[Myelopathy secondary to an aneurysmal bone cyst of thoracic spine]

Spinal aneurysmal bone cysts are very infrequent benign osteolytic lesions consisting of blood-filled cavities that are separated by osteo-connective septa and osteoclast-type giant cells. Clinically they manifest with local pain, neurological symptoms secondary to spinal cord compression, and fractures, deformities and vertebral instability. We report a case of an aneurysmal bone cyst in the thoracic spine with neurological signs and symptoms treated by means of a full microsurgical resection, with no associated neurological sequelae.

A 47-year-old woman, with no previous history of traumatic injuries, who was examined following several weeks with clinical signs and symptoms of paraesthesia in the lower limbs. Thoracic magnetic resonance imaging revealed the existence of a lytic lesion with clearly defined edges and marginal sclerosis in T4, in addition to involvement of the posterior vertebral elements and compression of the underlying spinal cord. The whole lesion was removed surgically, and the sensitive clinical symptoms disappeared after the procedure. The definite pathological diagnosis was spinal aneurysmal bone cyst.

Despite their low incidence, aneurysmal bone cysts of the spine must be taken into account in the differential diagnosis of spinal bone tumours as a possible cause of subacute or chronic compressive myelopathy. Full surgical removal of the tumour is considered the preferred treatment, which is often curative and is associated with a good prognosis of the patient in the long term.