Osteoid Osteoma of the Quadrilateral plate of acetabulum: A case report on an unusual cause of hip pain

Abstract

Introduction– Osteoid Osteomas are rare and extremely painful benign bone tumours. They are usually seen in children in the growing age group and young adults. The patients typically complain of bony pain during the night time and usually relieved with rest and salicylates. Osteoid Osteomas are commonly encountered in the limbs with Proximal femur/ Hip region and Tibial diaphysis being the usual locations. Pelvic locations are rare for osteoid osteoma and few cases have been published/ reported in literature. Case Presentation – A young female with long standing hip pain was diagnosed to have osteoid osteoma in an extremely rare location in her pelvic bone. After careful evaluation of the imaging the lesion was found to be in the Quadrilateral plate/Medial wall of acetabulum. After through pre-surgical planning she underwent the Gold-standard treatment for osteoid osteoma i.e., Computed Tomography (CT)- guided Radiofrequency Ablation (RFA). Immediate post-procedure the patient reported complete relief of her symptoms and has been symptoms-free for the past 2years of follow-up. Conclusion - A high level of clinical suspicion is warranted to keep osteoid osteoma as a differential diagnosis in a patient presenting with the relevant symptoms. They can be easily missed on Radiographs and CT is a clincher for diagnosis and unusual anatomic sites can harbour the same. A carefully planned Radiofrequency ablation under CT-guidance gives favourable and reliable results for treatment of osteoid osteomas.