Simple bone cyst is a bone lesion having a serous content localized in the metaphysis developing during the growth age. Its nature is atrophic, degenerative and its etiopathogenesis is unknown. It is classified in the pseudotumors of the bone with frequent occurence after histiocytic fibroma and exostosis. Incidence is greater in male sex at a ratio of 2:1 and most of the patients are 5 to 15 years of age; more than half of the cases are localized in the proximal humerus, less frequently in proximal femur and other locations. It is a painless lesion and therefore it is diagnosed secondary to a pathologic fracture or incidentally. Simple bone cyst is conventionally treated by curettage and bone grafting. But, primarily with the steroid injection technique popularized by Scaglietti et al.,[1] different types of surgery were described and advocated such as autologous bone marrow injection, multiple drilling, intramedullary nailing.

Aneurysmal bone cyst is an expansive pseudotumoral lesion of bone clinically characterised by pain and swelling. Structurally it is hyperemic and its genesis is unknown. It is most frequently observed from 10 to 20 years of age and there is a slight predilection for the female sex. Aneurysmal bone cyst constitutes 1–2% of all bone tumours.[ 2] It may be observed in any site of the skeleton but the most common sites are long bones of the lower limb, the vertebral column and the long bones of the upper limb. It may be observed in some areas of other tumors such as giant cell, brown tumor, chondroblastoma, osteoblastoma or it may be a hemorrhagic transformation of another previously affirmed tumor. They are generally progresive lesions but we occasionally encounter cases with small growth rate that slowly ossify without any treatment. This maturation is induced by radiation or selective arterial embolization. The choise of treatment is extraperiosteal excision and curettage associated with the use of local adjuvants such as phenol, liquid nitrogen, bone cement and bone grafting. Recurrence of 10–15% have been reported.