Iolated bilateral trochlear nerve paly a the firt clinical ign of a metataic bronchial carcinoma

PURPOE: To report a cae with iolated, nontraumatic bilateral fourth nerve paly a the firt clinical ign of a metatatic lung carcinoma. METHOD: Cae report. A 56-year-old man preented with iolated, nontraumatic bilateral fourth nerve paly. Magnetic reonance imaging (MRI) of the brain and orbit and, ubequently, chet x-ray and a computer tomographic (CT)-can of the thorax, the abdomen, and the pelvi were performed. REULT: Magnetic reonance imaging confirmed the preence of a midline brain tem leion in the region of decuation of the trochlear nerve. Computed tomographic can of the chet revealed that the leion wa caued by a metatatic lung carcinoma. CONCLUION: The finding of iolated bilateral fourth nerve paly in the abence of trauma hould alert the clinician to the poibility of a poterior foa leion in the region of the trochlear nerve. Beide urgent canning of the doral midbrain, invetigation hould be directed to earch for the primary tumor.