Simple bone cyst of lamina of lumbar spine: a case report.

STUDY DESIGN: A case report and literature review. OBJECTIVE: To describe an extremely rare simple bone cyst involving the lamina of the lumbar spine. SUMMARY OF BACKGROUND DATA: Simple bone cysts involving the spine are very rare. Moreover, the authors are unaware of any published report of a simple bone cyst involving the lamina of the spine. METHODS: A cystic lesion, incidentally identified in a patient with lumbar disc herniation of L5-S1, located at the left lamina of L5, was surgically treated with complete resection of the involved lamina and discectomy of L5-S1. Medical records, imaging studies, histologic findings, and related literature are reviewed in this study. RESULTS: Histologic examination of a section of the cystic lesion showed a thin fibrous lining membrane of the cyst surrounded by well-vascularized new bone formation. This result is consistent with the findings of previously reported simple bone cysts in other sites of the body, including the spine. CONCLUSION: This study suggests that a simple bone cyst may be included in the differential diagnosis of a cystic lesion of the posterior elements, especially laminae, of the spine.