The diagnosis and management of the alteration of the normal function of the oculomotor nerve (third cranial nerve) varies depending on the characteristics of the paralysis, the age of the patient, and the associated symptoms and signs. Oculomotor nerve palsy may be caused by lesions located anywhere from the oculomotor nucleus to the termination of the third nerve in the extraocular muscles. Although there have been significant advances in neuroimaging to facilitate early diagnosis, the management of a patient presenting with isolated oculomotor palsy is still challenging. This review tackles the case of a 52-year-old patient, with a history of pulmonary tuberculosis (at the age of five), referred to the Department of Ophthalmology, St. Spiridon Emergency Clinical Hospital, Iaşi, Romania. The patient had diplopia accompanied by right eyelid ptosis, symptoms that began suddenly 10 days before hospitalization. The clinical examination showed right eye grade II palpebral ptosis, exotropia with limitation of eyeball movements in adduction, supra-∕infraduction. Biomicroscopic examination of the anterior pole revealed the presence of anisocoria and light-near dissociation on the affected side. Numerous investigations were performed to identify the cause, starting with tumoral markers, which were within normal limits. Magnetic resonance angiography (MRA) was performed, and posterior communicating artery aneurysm was ruled out. The endocrinology examination and hormonal laboratory tests were also within normal parameters. Due to suspicions of generalized tuberculosis raised by the infectious disease doctor or presence of secondary lesions, thoraco-abdomino-pelvic computed tomography (CT) scan with contrast agent was done and its findings required gastroenterological exploration. After various explorations, the certainty diagnosis was set by histopathological examination, which revealed gastric adenocarcinoma.