METHODS Male, 5 FINAL DIAGNOSIS: Osteoblastoma Symptoms: - METHODS - Clinical Procedure: - Specialty: Oncology. OBJECTIVE Rare disease. BACKGROUND Osteoblastomas are relatively uncommon bone tumors that account for <1% of all bone tumors. They usually occur in the medullary region of the bone. As such, intraarticular osteoblastomas are quite rare. METHODS In this report, we present the case of a 5-year-old boy who presented with vague pain and subluxation of the hip joint due to an intraarticular osteoblastoma. Radiological examinations showed an irregular calcified mass lesion in the hip joint. The final diagnosis of osteoblastoma was made by histological examination. The patient's symptoms completely subsided following surgical removal of the tumor. CONCLUSIONS Osteoblastomas can occur in the intraarticular region. Although quite rare, osteoblastoma should be considered among the differential diagnoses for patients with pain and subluxation of the hip joint.