Chondromyxoid fibroma of the lumbar spine: is tumor recurrence to be expected after subtotal resection? Illustrative case.

backgroundChondromyxoid fibroma (CMF) is a rare tumor usually found in the epiphysis and metaphysis of long bones. In the absence of effective nonsurgical treatment modalities, radical tumor resection is recommended. Spinal CMFs present a unique surgical challenge making total tumor resection often impossible. Little is documented about the long-term prognosis of spinal CMFs after subtotal resection, but inferring from outcomes of extremity CMF surgery, tumor recurrence is to be expected after incomplete resection. OBSERVATIONS: The authors present a 6-year follow-up case of an incompletely resected large lumbar CMF involving the L5 vertebra. This case appears to be the largest documented spinal CMF with the longest follow-up period after subtotal resection. Despite a residual tumor in the proximity of the inferior L5 endplate on immediate postoperative imaging, the patient has remained asymptomatic and without soft tissue tumor progression or recurrence for more than 6 years (77 months). LESSONS: The long-term outcome of this case demonstrates that total tumor resection may not be necessary for long-term disease control. This finding is in agreement with 14 previously reported lumbar CMFs, with only 1 documented recurrence at 60 months. https://thejns.org/doi/abs/10.3171/CASE25350.