Giant-cell Tumor of Dorsal Vertebra Presenting as a Posterior Mediastinal Mass: A Rare Case Report

Abstract

Giant cell tumors (GCT) of bone also referred to as osteoclastoma or myeloid sarcoma are usually benign tumors but have the potential for local recurrence and metastasis. Giant cell tumors mostly involves the long bones with the proximal tibia and distal femur sites. Giant cell tumors of the spine presenting above the level of the sacrum is relatively less common. We report a patient with GCT arising from dorsal vertebrae and presenting as a huge mediastinal mass. A 25-year-old female presented with bilateral lower limb weakness, breathlessness, and difficulty in speaking. Chest X-ray showed bilateral upper lobe mass. On further evaluation with contrast-enhanced computed tomography (CECT) of the thorax a large well defined heterogeneously enhancing posterior mediastinal lesion with necrotic areas within and bony infiltration was noted. Sequential chest X-ray was suggestive of rapid progression within 15 days. Ultrasound-guided biopsy of mass lesion revealed features of giant cell tumor with immunohistochemical markers strongly positive for CD68, negative for S100, and β -HCG. The patient was subsequently started on denosumab given unresectable pulmonary metastasis.