A case study of unusual benign osseous lesion of the L5 lamina.

BACKGROUND

The differential diagnosis of benign-appearing posterior element lesions is complex.

OBJECTIVE

To explore the etiology of an unusual benign lesion found on the lamina of L5 described in a case report.

METHODS

Case report. The patient's medical, surgical and imaging histories as well as medical literature were reviewed.

RESULTS

A 35-year old male complained of low back pain radiating to both legs for 5 months. Abdominal CT scan 1 year prior as well as post symptom-onset CT and MRI showed a well-corticated lesion lateral to the spinous process of L5. After failed rehabilitation and injection, operation revealed normal cortical bone. Pain was not markedly relieved post-operatively.

CONCLUSION

The pre-surgical differential diagnosis of this lesion included osteosarcoma and osteoid osteoma, however benign pathological results suggest the possibility of atypical spina bifida occulta, Baastrup changes, atypical sacralization of L5, or a resolved fracture with heterotopic ossification.