Fibromatosis involving the epidural space.

A 16-year-old boy was in his usual state of good health until 2 weeks before admission when a tingling sensation over both knees developed and several episodes of falling occurred because of leg weakness. He had not noted symptoms in his upper extremities but did have difficulty with urination and erections. Physical examination was significant for hyperactive reflexes in both the upper and lower extremities with bilateral plantar reflexes, a positive Romberg sign, and a sensory level at C4–5. Findings on magnetic resonance (MR) imaging of the brain were within normal limits. MR of the cervical and thoracic spine, performed both without and after the intravenous administration of gadopentetate dimeglumine, showed a moderately inhomogeneous circumferential epidural mass extending from the level of C-2 to T-5, bilateral apical/paravertebral masses at the level of T1–2 that appeared continuous with the epidural disease, and a poorly circumscribed mass in the left side of the neck (Fig 1). A faintly enhancing, poorly marginated mass was noted in the superficial soft tissues overlying the spinous processes from C-2 to C-5 that was not clearly continuous with the epidural disease. The subarachnoid space was preserved at all levels except at T2–3, where the mass just impinged on the spinal cord (not shown). Computed tomography (CT) showed multiple round calcifications within the epidural space and within the paravertebral masses but did not show any abnormality corresponding to the linear and curvilinear signal voids noted on MR (Fig 2). An open biopsy of paraspinal tissue from T-2 revealed hypocellular bundles of collagen displacing and invading connective tissue and skeletal muscle (Fig 3). The final pathologic diagnosis was fibromatosis. The patient was placed on steroids and a chemotherapeutic regimen consisting of vincristine, dactinomycin, cyclophosphamide, and tamoxifen every 3 weeks for 7 months. Follow-up scans showed modest regression of the epidural mass (Fig 4). This mild improvement in cord compression at T2–3 produced dramatic resolution of long-tract signs and return of normal motor strength and genitourinary function.