Thoracoabdominal chordoma in a pediatric patient. A rare entity.

Introduction: Chordoma is a rare, slow-growing notochordal neoplasm typical of adults. Less than 5% of the cases occur in children, where they are located at the skull base. Treatment involves surgical resection with or without radiotherapy.

Clinical Case: 14-month-old patient with a left dorsal lumbar mass, pain, and limited mobility in the lower limbs. MRI showed a left paravertebral mass infiltrating the spinal canal (T11-L1), in contact with the parietal pleura, along with abdominal extension. Chordoma diagnosis was established based on percutaneous biopsy. Full resection without safety margins was carried out using the posterior approach. One month later, tumor recurrence caused hemothorax, pleural infiltration, and rib infiltration. Two chemotherapy cycles were administered, with a good response. Reintervention was successfully conducted one month later. After 9 months, the patient is free from disease, under chemotherapy treatment and proton therapy.

Discussion: Although unusual, chordoma is included within the differential diagnosis of retroperitoneal masses. Prognosis depends on full resection.