Chondroid chordoma of the L5 spinous process and lamina: a case report.

Chordoma is a rare bone tumor that originates from the remnants of the notochord. These tumors have axial distribution particularly at the upper and lower ends of the vertebral column. This paper reports a rare occurrence of a chordoma in the posterior elements of the L5 vertebra. A differential diagnosis of a benign tumor (giant cell tumor, aneurysmal bone cyst or osteoblastoma) was made initially. Other differential diagnoses included plasmacytoma and metastasis. The tumor was removed enbloc. Histopathological examination revealed the tumor mass to be chordoma. There were no clinical or radiological signs of recurrence at 21 months follow-up. Chordomas are tumors of the axial skeleton. However, they may occur in unusual sites in ectopic notochordal tissue. The case is being presented for its unusual site of occurrence.