Osteochondroma of inferior articular process in lumbar spine causing spinal stenosis: a case report

Abstract

Osteochondroma is the most common benign bone tumor; however, spinal involvement is uncommon and may result in significant neurological compromise when neural structures are compressed. Osteochondroma arising from the lumbar facet joint is particularly rare and can clinically mimic degenerative spinal disorders. We report the case of a 47-year-old woman who presented with chronic low back pain and progressive right lower limb radiculopathy. Computed tomography demonstrated a 21 × 18 × 16 mm osseous lesion arising from the right inferior articular process of L3, showing clear cortical and medullary continuity with the parent vertebra. Magnetic resonance imaging revealed L3–L4 spinal canal stenosis with compression of the cauda equina, and the cartilage cap measured approximately 3 mm on T2-weighted imaging. The patient underwent posterior decompression with en bloc excision of the lesion. Segmental stability was preserved after facetectomy, and instrumentation was not required. Histopathological examination confirmed the diagnosis of osteochondroma. At the 12-month follow-up, the patient remained asymptomatic, with no radiological evidence of recurrence or instability. This case highlights the importance of comprehensive imaging evaluation, careful assessment of postoperative spinal stability, and complete excision including the cartilage cap to prevent recurrence.