Medical Mystery of the Week

       You are asked to make a diagnosis in this patient merely by looking at photos of his face.

                   "Look at me"                "Show me your teeth"        Response to funny joke. 

      DIAGNOSIS: Subthalamic lymphoma. Note the patient can smile on command,  a function dependent on intact lower (facial nerve) and upper motor neuron function. However, when stimulated emotionslly (funny joke)  his smile is limited to the left side of his face - placing the lesion somewhere in his emotional (limbic) system, in this case in the subthalamic region. This is most often secondary to a vascular event, but in the presented case it is due to a subthalamic lymphoma.