A 60-year-old woman presented with a 5-month history of paraesthesias on both feet, progressively extending upwards, bilateral leg weakness and hypoestesia. Neurological status progressively worsened, leading to paraparesis. In the last 2 weeks, she started complaining of urinary frequency and constipation. On neurological examination, the patient had diffuse lower-extremities weakness (left leg 1–2/5, right leg 3–4/5), was not able to maintain a straight posture, had a T9 sensory level and had symmetrical hyper-reflexia at the knees and ankles with left clonus; both great-toes were upgoing.

An MRI exam of the thoracic spine showed an extradural mass lesion at T9–T10, resulting in significant ventrolateral spinal cord displacement and compression; the tumour had an overall dumb-bell shape extending in the left paravertebral space through an enlarged vertebral foramen (fig 1C,D). The lesion appeared isointense on both T2- and T1-weighted images (fig 1A,B) with moderate and inhomogeneous enhancement after contrast injection (fig1C,D).

A presumptive preoperative diagnosis of extradural schwannoma or neurofibroma was done.

The patient underwent laminectomy from …