Primary chondrosarcoma arising from the L5 transverse process: A rare cause of chronic low back pain

Chronic low back pain is a highly prevalent condition; however, primary spinal malignancies, though rare, carry critical clinical implications. Chondrosarcoma is a slow-growing malignant bone tumor, with spinal involvement accounting for <10% of cases. Tumors originating from the posterior vertebral elements, particularly the transverse process, are exceedingly uncommon and frequently result in delayed diagnosis due to their indolent clinical course.

We present a 51-year-old male with a 5-year history of intermittent low back pain who developed a progressively noticeable lumbar mass. Advanced imaging demonstrated a heterogeneous, partially calcified lesion arising from the left L5 transverse process with extension into the adjacent paraspinal soft tissues. Histopathological evaluation confirmed a Grade 1 chondrosarcoma. The patient underwent en bloc resection of the tumor, including the involved transverse process, through a posterior approach under intraoperative neuromonitoring. Postoperative imaging showed no radiological evidence of residual tumor; no adjuvant therapy was administered. At the 1-year follow-up, the patient remained asymptomatic with no radiological evidence of recurrence.

Primary chondrosarcoma of the lumbar transverse process represents an exceptionally rare entity that should be considered in patients presenting with long-standing back pain accompanied by a palpable or fixed paraspinal mass or other suspicious imaging findings. Complete en bloc surgical resection remains the cornerstone of treatment and was associated with a favorable early outcome in this case, though long-term surveillance is essential, given the potential for late recurrence.