Postoperative Development of Desmoid Tumor Following Surgical Correction of Adult Spinal Deformity: Case Report and Review of the Literature

Background Desmoid tumors are known to be rare and relatively slow growing with locally invasive histology and high recurrence rates. A rare subset of these tumors occurs adjacent to the spinal column after surgery. Since 1961, only 6 cases of postoperative paraspinal desmoid tumor have been reported. This report is the first to describe the occurrence of a paraspinal desmoid tumor after surgical correction of a spinal deformity. Case Description A 56-year-old woman with multiple sclerosis reported 2–3 years of progressively worsening mid and low back pain that was worse with standing and ambulation and almost completely relieved with lying flat. Standing anteroposterior scoliosis radiographs revealed a thoracolumbar spinal deformity, which was surgically corrected with a T4 pelvis spinal fixation and fusion. At her 2-year postoperative clinic visit the patient reported good improvement in her preoperative symptoms but felt a fullness in her right upper back and neck that was nontender. Magnetic resonance imaging revealed a large tumor in this region. The tumor was resected en bloc, and pathology noted a 14.5 cm × 8.7 cm × 4.2 cm mass with spindle cell proliferation and positive staining for β-catenin (mutated gene found in 85% of desmoid tumors). Conclusions This is the first report of a postoperative desmoid tumor after spinal deformity correction and the seventh reported case in the spine literature. All reported cases have been women aged 39–57 years. The patient will be followed closely with magnetic resonance imaging given the known high local recurrence rate of this tumor.