Persistent Radiating Back Pain in an Adolescent – A Case of Nonresectable Sacral Osteosarcoma

Background: Osteosarcoma is the most common primary malignant bone tumor, typically arising in the long bones. Pelvic osteosarcoma, particularly in the sacrum, is rare and poses therapeutic challenges. Clinical Description: A 13-year-old girl presented with a shooting type of pain in both lower limbs with paraparesis. Imaging revealed a large sacral mass with osteoid-type mineralization. Biopsy showed spindle cells without osteoid elements, but immunohistochemistry was positive for Special AT-rich Sequence-Binding Protein 2 (SATB2). Correlating the presence of osteoid in radiography and SATB2 positivity, a diagnosis of osteosarcoma was made. Management and Outcome: The lesion was deemed unresectable due to its strategic location. The patient received neoadjuvant chemotherapy, but the reassessment imaging showed no improvement. As pain persisted, palliative radiotherapy was administered, resulting in a reasonable duration of symptomatic relief with improved mobility; only to have recurrence of symptoms, which turned out to be fatal. Conclusion: In adolescents with persistent back pain and sensory disturbances, bone tumors should be considered as a differential diagnosis. Unresectable sacral osteosarcoma is fatal. While chemotherapy provides no improvement, radiotherapy can provide a reasonable period of symptom relief, though not curative.