Lumbar Vertebral Fracture Through a Pre-Existing Schmorl's Node Mimicking Histopathologically a Low-Grade Chondrosarcoma.

ABSTRACT

The aim of this paper is to present a unique, to the best of our knowledge, case of a patient with a fracture of the first lumbar vertebra (L1), which occurred through a pre-existing Schmorl's node (SN), with histopathological characteristics mimicking a low-grade chondrosarcoma that initially led to a false diagnosis. A 54-year-old woman tripped and fell to the ground, sustaining a fracture of the L1 vertebral body. She was treated conservatively with gradual mobilization using a thoracolumbar brace for six weeks. Due to persistent pain and her inability to achieve full mobilization, she was offered vertebral kyphoplasty. During the same operative session and just before the kyphoplasty, she underwent a core-needle biopsy of the affected area. Following her operation, she reported a gradual, yet quick and full remission of her symptoms. The pathology report indicated findings consistent with a low to mid-grade chondrosarcoma. A re-evaluation of the specimen by a different pathologist confirmed the diagnosis of low-grade chondrosarcoma. Subsequently, she underwent full oncological staging, which was negative for metastases. Additional imaging studies failed to show signs of local disease progression. Due to the discordance between the pathology reports and the imaging and clinical findings, her case was referred to our specialized center for spinal tumor surgery. A new pathological re-evaluation of the biopsy samples was performed, and the diagnosis of low-grade chondrosarcoma was once again confirmed. However, during the multidisciplinary tumor (MDT) meeting that followed, and after careful evaluation of subsequent imaging studies that showed signs of local improvement and due to the complete lack of symptoms, the histopathological findings were re-evaluated and attributed to the fracture occurring through a pre-existing SN penetrating the cancellous bone of the vertebra. This complex situation contributed to histopathological findings consistent with a well-differentiated chondrosarcoma. The patient remains symptom-free 10 months following her operation and has fully returned to her previous activities. Our unique case highlights the importance of an MDT meeting when evaluating patients with musculoskeletal tumors and emphasizes the need for increased awareness when clinical findings and imaging studies are in discordance with histopathology reports.