Pathological examinations confirmed the diagnosis of osteochondroma with the large bursa formation. Clinical examination 19 months postoperatively showed an uneventful clinical course. Large bursa formation associated with osteochondroma has rarely been reported. Figure 1 . Figure 2 .
Oblique radiogram shows a mushroom-shaped bony protrusion directed towards the chest wall.
Figure 3 . Neither fuzzy margins of the cartilage cap nor the presence of a lucent zone within the osteochondroma is defined. He was admitted to our institution in April 1997 with a rapidly growing mass at the inferior and lateral borders of his right scapula. The patient noticed size variation of the mass during a 1-month period. His past and family history were not contributory.