Telangiectatic osteosarcoma of the lumbar spine in a 15‑Year‑Old Girl: A Diagnostic Pitfall Mimicking Benign Lesions

Background: Telangiectatic osteosarcoma (TOS) is a rare, aggressive osteosarcoma variant that can mimic benign lesions such as aneurysmal bone cyst (ABC) or giant cell tumor (GCT). Its occurrence in the spine is exceptional and may lead to diagnostic delays.
Case: We report the case of a 14‑year‑old girl presenting with progressive paraparesis and low‑back pain. MRI revealed an expansile lytic lesion at L3. Initial histopathology after decompressive laminectomy suggested a giant cell–rich lesion. The patient improved transiently, but symptoms recurred within six weeks. A second surgery with anterior tumor excision was performed; histology then favored an aneurysmal bone cyst. Owing to the rapid recurrence and aggressive local behavior, a third expert histopathological review confirmed telangiectatic osteosarcoma.
Conclusion: Telangiectatic osteosarcoma can closely mimic benign cystic bone lesions. Awareness of its aggressive evolution and careful histopathological review are essential for accurate diagnosis and timely oncologic management.