Sopta, J. (24328547800)J. (24328547800)SoptaAtanacković, M. (6603459157)M. (6603459157)AtanackovićVukmirović, S. (6603135755)S. (6603135755)VukmirovićZlatković, M. (36640317400)M. (36640317400)ZlatkovićDordević, A. (6603291241)A. (6603291241)Dordević2025-06-122025-06-122000https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034530350&partnerID=40&md5=1dc738d159accd8ca33f18ecff4a59afhttps://remedy.med.bg.ac.rs/handle/123456789/1457Osteoid osteoma is a benign osteoblastic lesion of bone. Generally, osteoid osteoma doesn't have recurrences. Radical surgery offers a cure and only few cases of recurrence were published. From 1979 till 1998., 153 osteoid osteoma (OO) were introduced in Register of bone and joint tumors at the Institute of pathology, School of medicine, Belgrade. The tumor was 1,7 times more frequent in males (males 97, females 56). The lesion occured predominantly (50% or 76 cases) in the second decade of life. The youngest patient was 22 months, the oldest was 54 years old. The most common involved bone was femur (64 cases, 41,8%), but the rare locations were: index (6), polex (4), os ilei (1), os pubis (1), clavicula (1). We reviewed 2 (two) cases of OO recurrent tumors after en-bloc resection. In the first case, a 9 year-old boy, curetage was made in 1992, and OO was identified histopathologically. One year after that (1993.) the patient had identical symptoms and radical surgical therapy was performed; in the bloc-resection part of bone calcified a nidus was present. In 1998, the boy had typical clinical signs again, en-bloc tumor excision was repeated, and then the tumor which has a shape of a band (3,5×1,0cm) was histopathologically described. It was a reason to think about differential-diagnosis between osteoblastoma and OO. The second case was an 8 year-old male patient, in 1982, to whom an en-bloc resection was made, and two nidi of OO were described. One was 1,5×1,5cm, and the second was 0,3×0,3 cm. The smaller was beside the bigger one, separated each to other with a fibrovascular zone. Five years later patient had recurrent specific clinical symptoms; which led to a second en-bloc resection. Histopathologically OO was confirmed.Osteoid osteomaRecurrence