Primary malignancy in giant cell tumor of thoracic vertebrae: A case report.

Rationale: Primary malignancy in giant cell tumor of bone (PMGCTB) is extremely unusual. PMGCTB in the thoracic vertebrae is particularly rare.

Patients Concerns: A 23-year-old man was admitted with a chief complaint of chest pain associated with cough for approximately 3 days. Physical examination revealed a palpable, immobile, tender, 7 cm mass in the right paravertebral area of the thoracolumbar spine.

Diagnosis: Computed tomography images revealed an osteolytic, expansive, and eccentric lesion on the vertebral bodies and right accessory processes with spinal cord compression in the thoracic vertebra, with right rib also having bone destruction. Magnetic resonance imaging revealed multiple fluid-fluid levels occupying more than one-third of the lesions. On the basis of the imaging and pathological findings, the final pathological diagnosis was PMGCTB with aneurysmal bone cyst.

Interventions: The patient underwent successful wide spondylectomy of T9/10 to remove the tumor, and adjuvant chemotherapy based on the protocol used for osteosarcoma.

Outcomes: After 4 years of follow-up, there is no clinical or radiological evidence of recurrence.

Lessons: PMGCTB is difficult to distinguish from giant cell tumor of bone. PMGCTB should be considered when lesions appear with multiple fluid-fluid levels and soft tissue mass.