Affiliations: [a] College of Osteopathic Medicine, University of New England, Biddeford, ME, USA | [b] Department of Physical Medicine and Rehabilitation, The University of Michigan, Ann Arbor, MI, USA | [c] Department of Orthopedic Surgery, The University of Michigan, Ann Arbor, MI, USA | [d] Department of Pathology, The University of Michigan, Ann Arbor, MI, USA | [e] Department of Radiology, The University of Michigan, Ann Arbor, MI, USA
Correspondence:
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Corresponding author: Andrew J. Haig, Physical Medicine and Rehabilitation, University of Michigan, 325 E. Eisenhower, Ann Arbor, MI 48108, USA. Tel.: +1 734 763 4200; Fax: +1 734 660 0083; E-mail: andyhaig@umich.edu
Abstract: 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.
Keywords: Lumbar spine, back pain, congenital anomaly, sacralization of L5, spinous process, facet joint
