Isolated bilateral trochlear nerve palsy as the first clinical sign of a metastasic bronchial carcinoma

PURPOSE: To report a case with isolated, nontraumatic bilateral fourth nerv e palsy as the first clinical sign of a metastatic lung carcinoma. METHODS: Case report. A 56-year-old man presented with isolated, nontraumat ic bilateral fourth nerve palsy. Magnetic resonance imaging (MRI) of the br ain and orbits and, subsequently, chest x-ray and a computer tomographic (C T)-scan of the thorax, the abdomen, and the pelvis were performed. RESULTS: Magnetic resonance imaging confirmed the presence of a midline bra in stem lesion in the region of decussation of the trochlear nerves. Comput ed tomographic scan of the chest revealed that the lesion was caused by a m etastatic lung carcinoma. CONCLUSION: The findings of isolated bilateral fourth nerve palsy in the ab sence of trauma should alert the clinician to the possibility of a posterio r fossa lesion in the region of the trochlear nerves. Besides urgent scanni ng of the dorsal midbrain, investigations should be directed to search for the primary tumor. (C) 2001 by Elsevier Science Inc. All rights reserved.