Brown tumor of the cervical spine with primary hyperparathyroidism: A case report and literature review.

RATIONALE: Brown tumor (BT), an uncommon focal lytic bone tumor, is a non-neoplastic and reactive process caused by increased osteoclastic activity and fibroblastic proliferation in primary or secondary hyperparathyroidism. Vertebral tumor causing neural compression is relatively rare, especially in the cervical spine. PATIENT CONCERNS: A 29-year-old man developed neck pain and arm radicular pain 4 months ago, with the level of serum calcium significantly higher than normal. Computed tomography scan of the cervical spine revealed an expansile lytic lesion occupying the C6 body, left pedicle, and left lamina of C5-6. DIAGNOSES: Osteoclastoma according to imaging and histopathological results. INTERVENTIONS: A laminectomy of C5-6 was performed. OUTCOMES: One month later, he was re-hospitalized due to nausea and vomiting and the serum calcium, was still, kept at a high level. Additionally, the parathormone (PTH) was greatly higher than normal. BT with primary hyperparathyroidism due to the parathyroid tumor was considered. After the surgery of the right parathyroid gland was performed, serum calcium and PTH both decreased, and computed tomography showed good recovery. LESSONS: BTs might be misdiagnosed as other giant cell tumors, thus when giant cell tumors are considered, serum calcium and PTH examination may be needed to exclude BTs.