Pain and neuroma formation in Wallenberg's lateral medullary syndrome.

We report a patient with a Wallenberg's lateral medullary syndrome in which pain was a prominent feature. This led to substitution of the original and correct diagnosis by that of a thalamic syndrome for which a prefrontal leucotomy was performed. The patient died some years later from a myocardial infarction and autopsy was performed. In the dorsolateral part of the medulla oblongata a cavity was found in which aberrant nerve fibres with neuroma-like formations could be seen. These fibres coursed along blood vessels, and penetrated from the surface of the medulla oblongata. On the base of the clinico-pathological correlations, it is conjectured that destruction of the lateral reticular formation cannot be the sole cause of the severe pain.