GRAND ROUNDS

Case #1: A specimen was obtained using MRI guiding biopsy technique. Hystology: benign spindle cell Schwannoma.

Case #2: A specimen was obtained using CT guidance. Hystology: malignant Schwannoma.

Schwannomas are derived from the nerve sheath and they are thought to be arising from the peripheral nerve sheath and secondary to proliferation of the peripheral nerve sheath, leading to cancer. More commonly, these tumors are seen in cranial nerves, in contrast to neurofibromatosis which are generally seen in the peripheral nerves.

Acoustic neuromas are another type of Schwannoma. These type of tumors are most commonly benign. Histology of Schwannomas is generally benign. S100 antibody stainings have been used to identify the benign tumors. Malignant tumors in general are found to be hypercellular.

It's noteworthy that these tumors are extremely rare and only less than 100 cases of these tumors have been reported. These tumors are slow growing and spread through the lymphatic system is uncommon. Most commonly these tumors are spread via the vasculature.

Treatment for these tumors are mainly surgical. Radiation therapy has shown to have some palliation effect. Long term survival for these tumors are 40-45 percent in five years.