Activation of the arachidonic acid metabolic pathway and induction of sleep disturbance by sacral osteoblastoma: A case report

: Osteoblastomas are benign bone tumors that produce prostaglandin and promote inflammation. The aim of the present study was to describe the clinical and radiological characteristics of a pediatric osteoblastoma case over an 8-month postoperative follow-up. The case involved an 11-year-old female patient with normal somatic development, presenting with a chief complaint of sleep disturbance. The patient had no spontaneous pain or other readily evident possible causes. Magnetic resonance imaging (MRI) revealed a neoplastic lesion in the sacrum, with peritumoral edema. Intraoperative fast-frozen biopsy raised the suspicion of osteosarcoma. However, the final diagnosis was osteoblastoma and a second operation was performed for total resection. The edematous peritumoral bone and muscle tissues were preserved. Following total removal of the tumor, the sleep disturbance resolved. Eight months after the surgery, MRI revealed no recurrence of the tumor and reduction of the peritumoral edema. On immunohistochemical examination, cyclooxygenase (COX)-1 and COX-2 were strongly positive, indicating that the tumor activated the arachidonic acid metabolic pathway and produced prostaglandin. The inflammatory process subsequently promoted the development of peritumoral edema and induced the sleep disturbance.