Contiguous Lumbar Vertebral Involvement with Vertebral Collapse in Giant Cell Tumor: A Usual Tumor with an Unusual Presentation.

Giant cell tumor (GCT) is a primary bone tumor of long bones, which can rarely involve the vertebrae. Contiguous vertebral involvement by GCT is a rare presentation and poses a diagnostic dilemma on imaging. We report a case of GCT involving three contiguous lumbar vertebrae causing vertebral collapse along with a large soft tissue component. Considering the site and clinical presentation, possibilities of a round cell tumor with large extraosseous soft tissue component and malignant neurogenic tumor were suggested on initial radiological examination but histopathology confirmed the diagnosis of GCT. It is important to diagnose this entity correctly because of totally different lines of management. In our case, initial surgical management was excluded in view of high surgical morbidity and, thereby, adjuvant therapy with denosumab was planned.