Simple bone cyst with pathologic lumbar pedicle fracture: a case report.

STUDY DESIGN: A case report and review of the literature are presented. OBJECTIVE: To describe an unusual simple bone cyst involving the pedicle of lumbar spine. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, only nine cases of a simple bone cyst involving the spine have been reported. Most of these reports have described mild back or neck pain because the presenting symptoms or cysts were found incidentally. In the reported case, acute severe back pain with radiating pain developed. Therefore, the study focus was on the unusual location, the presenting symptoms, and its spinal involvement. METHODS: A cystic lesion involving the left pedicle of the first lumber vertebra was identified in a 53-year-old woman with sudden-onset severe back pain with pain radiating to the left leg. Surgical resection was undertaken along with review of the patient's medical record, imaging studies, microscopic findings of the lesion, and the related literature. RESULTS: Microscopic examination of the cystic lesion corresponded with the findings of a simple bone cyst. A thin fibrous membrane with reactive bone formation was identified without evidence of hemorrhage. A favorable result was achieved by surgical resection. CONCLUSIONS: This case study suggests that a simple bone cyst may be found in any portion of the spine, including the pedicle. Severe resting pain would be elicited by a pathologic fracture of the pedicle. Direct nerve compression by the fractured fragment and chemical irritation by cystic fluid would be compatible with the observed clinical manifestations.