Primary Aneurysmal Bone Cyst of Sacrum: A Case Report of a 12 years old boy from Pakistan.

Aneurysmal bone cysts are locally invasive, benign lesions usually found in the spine or metaphysis of long bones. They can be primary (idiopathic) or secondary to other bone pathologies. Primary aneurysmal bone cyst usually occurs in the first two decades of life. We report a 12 years old male, a known case of Type-1 diabetes mellitus, with lower back pain radiating to the right lower limb for the past two months following a fall. There were no neurological deficits, although straight leg raises and Faber's tests were positive. Neuroimaging suggested an enhancing 7 x 8 mm lesion involving the lamina of the first sacral vertebra with protrusion into the spinal canal. Bone scan ruled out metastatic pathology. Excision of the lesion with laminectomy and foraminotomy was done. Histopathology was suggestive of aneurysmal bone cyst. The patient is living a healthy life. Upfront surgical excision without preoperative embolization and expensive medical therapies can be an option in resource-limited settings.