Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 7 4 2022 04 05 157 8 Arvin Najafi Department of Orthopedic Surgery, Shahid Madani Hospital, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran Dorsa Hadavi Department of Radiology, Shahid Madani Hospital, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran Pooyan Jalalpour Orthopedic Surgery Ward, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2021 08 27 2022 02 26 Background: Osteochondroma is the most common benign tumor of the bone.   Case Report: In this case, we present a young patient complaining of sensation of a mass in her abdomen since a few weeks ago and abdominal pain, which caused her visit to the clinic. Imaging studies revealed a well-defined lobulated lesion, and pathological examination was correlated with osteochondroma of the iliac bone.   Conclusion: This site for osteochondroma is very rare, and this case was the solitary type.   Osteochondroma; Pelvic Neoplasm; Diagnosis https://jost.tums.ac.ir/index.php/jost/article/view/308 https://jost.tums.ac.ir/index.php/jost/article/download/308/249