Unusual location of osteochondroma over the scapular spine in a 12-year-old boy: a rare case report

Abstract

Osteochondroma is the most common benign bone tumour, typically occurring in the metaphysis of long bones such as the distal femur, proximal tibia, and proximal humerus. Involvement of flat bones like the scapula is uncommon, and osteochondroma arising from the spine of the scapula is particularly rare. A 12-year-old boy presented with a gradually increasing swelling over the right upper back for one year without history of trauma or systemic illness. Clinical examination revealed a firm, immobile swelling measuring approximately 3×3 cm over the posteromedial aspect of the upper scapula with normal overlying skin and no neurovascular deficits. Shoulder range of motion was full and painless. Radiographs of the right shoulder demonstrated a well-defined bony outgrowth arising from the spine of the scapula. CT scan revealed a lobulated expansile bony lesion measuring 3.1×3.2×2.6 cm in the posteromedial aspect of the scapular spine extending toward the superior angle. MRI showed a cartilage-capped bony projection with continuity of cortex and medullary cavity and a cartilage cap thickness of approximately 5 mm, consistent with osteochondroma. The lesion was excised surgically through a posterior approach. Histopathological examination confirmed the diagnosis of osteochondroma. The postoperative period was uneventful, and the patient regained full shoulder function. Osteochondroma arising from the spine of the scapula is rare but should be considered in adolescents presenting with a painless scapular swelling. Complete surgical excision provides excellent outcomes and prevents recurrence.