The patient went on to have a left hemilaminectomy and excision of an extradural tumor. Intra-operatively, the lesion was noted to erode through anterior vertebral body with the T12 nerve root traveling through the lesion. It derived its blood supply from the intercostal artery.

Histology

MACROSCOPIC DESCRIPTION:
Left T12/L1 extradural content/tumor: Six pieces of firm white to hemorrhagic tissue

MICROSCOPIC DESCRIPTION:
Sections demonstrate a benign spindled lesion. The lesion shows broad areas of sclerosis and low cellularity as well as focal Verrocay bodies. Hyalinised vasculature is noted. An occasional enlarged and hyperchromatic cell nucleus is present, however no necrosis is seen and the mitotic rate is not elevated. A nerve ganglion is seen at the lesion edge.

DIAGNOSIS: Schwannoma.