Paraneoplastic neurologic syndrome (PNS) is an uncommon manifestation of cancer that is not caused by the tumor or metastasis. Trigeminal neuralgia (TN) is an initial symptom of this disease, but it has rarely been reported in the literature. Here, we report the case of a 76-year-old woman who presented with classic TN, followed by limbic encephalitis due to an underlying ovarian intestinal-type mucinous borderline tumor, with the presence of anti-Hu antibodies. She recovered quickly after removal of the tumor and was essentially free of symptoms 2 weeks after surgery. Because PNS precedes the tumor in approximately 60% of cases, its rapid detection and treatment are crucial. Therefore, we propose that PNS be considered during the management of TN when brain imaging is normal, as it is followed by other central and/or peripheral neurological manifestations as well as the presence of systemic symptoms such as anemia, fatigability, loss of appetite, or weight loss.