9/21/2004 Case 3: Cellular schwannoma

Clinical History:

JM is an 18 year old male with a 6 month history of progressive upper extremity paresthesias and mild spasticity. Symptoms began with tingling in the left shoulder that spread to the ulnar aspect of the left arm which then became numb. The patient became unable to run and had to "drag" his legs. The sensory symptoms spread to his right upper extremity. There was no history of incontinence. On admission, the patient was alert, oriented and appropriate with fluent speech. Cranial nerves were nonnal. Strength was 515 in all muscle gtoups. Gait showed trace spasticity. There was hemibody sensory loss most marked on the left at T12 and below. Joint position sense was preserved. DTR were + 1 at all levels and symmetric in the UE and +3 bilaterally in the LE at all Ievels. MRI showed a large intradural extramedullary tumor at C7-Tl which was homogeneously enhancing in the anterior and left spinal canal compressing the spinal cord to the right. No other lesions wore fuund in the eNS. The tumor was excised.

Diagnostic Notes:

The slide showed an encapsulated spindle cell neoplasm with mostly Antoni A patterns but foci with loose Antoni B tissue. The tumor cell nuclei were hyperchromatic and fairly uniform . There were the usual thick-walled vessels of a Schwannoma . Finally, there were several mitotic figures, easily found in the slides submitted. Dr Weidenheim offered a diagnosis of "Cellular SchwannomaH • There was some discussion about the diagnosis, since some present (Dr Miller, for one) are of the opinion that these are not the wholly benign lesions they are represented as in most of the literature of cellular Schwannoma. Dr Miller cited several studies that mitotic figures in Schwannomas suggested a locally aggressive behavior and noted that a study he had done of eighth nerve tumors (Light et alia, J Neuro-otology) demonstrating with a strong p -value that mitotic figures over a certain threshold number, or a MIB1 above a certain threshold, were strong predictors of recurrence despite gross total excision . There was no dissent about this being a Schwann cell neoplasm, however , except for a brief suggestion that a differential with a smooth muscle neoplasm should have been considered.

Slide Image:

view high resolution slide image