[Aneurysmal bone cyst of the left 5th rib]

A case of aneurysmal bone cyst of the left 5th rib is reported. A 57-year-old male complained of palpable lump and pain on his back. Chest X ray and CT showed expansive tumor arid pathological fracture of the left 5th rib. The tumor and the adjacent segments of the 4th and 5th ribs were resected en bloc. The pathological examination showed multiple blood filled spaces and fibrous trabeculae, confirming the diagnosis of aneurysmal bone cyst. He has been followed up for 3 years and 6 months with no signs of recurrence.