TY - JOUR T1 - Initial enlargement of the opposite pupil as a false localising sign in intraparenchymal frontal haemorrhage. JF - Journal of Neurology, Neurosurgery & Psychiatry JO - J Neurol Neurosurg Psychiatry SP - 1126 LP - 1128 DO - 10.1136/jnnp.57.9.1126 VL - 57 IS - 9 AU - R Chen AU - R Sahjpaul AU - R F Del Maestro AU - L Assis AU - G B Young Y1 - 1994/09/01 UR - http://jnnp.bmj.com/content/57/9/1126.abstract N2 - Ipsilateral third nerve palsy with early pupillary enlargement is an important sign of transtentorial herniation from a supratentorial mass lesion. A case of frontal, intraparenchymal haemorrhage is reported in which the first ocular manifestation of transtentorial herniation was enlargement of the contralateral pupil. The ipsilateral pupil dilated only after complete oculomotor palsy of the contralateral eye. After partial frontal lobectomy and removal of blood clot, the ipsilateral third nerve recovered before the contralateral third nerve. Clinical findings localised the contralateral third nerve lesion to an extra-axial site. The possible mechanisms of contralateral third nerve compression are discussed. This seems to be the first example of pupillary enlargement as a false localising sign from a contralateral, supratentorial, intraparenchymal mass lesion. ER -