Breast cancer's hidden partner: meningoencephalitis as a paraneoplastic revelation: a rare presentation of invasive ductal carcinoma of breast: a case report.

Introduction and importance: Paraneoplastic neurologic syndromes encompass a group of neurologic disorders arising from pathological processes unrelated to metastasis, metabolic disturbances, infections, coagulopathy, or treatment-related side effects. These syndromes can affect various regions of the nervous system, resulting in diverse clinical manifestations. Case presentation: The authors present a rare case of anti-amphiphysin-associated meningoencephalitis in a South Asian Pakistani woman. Initially, the patient was managed for suspected infectious meningitis, but empirical treatment failed to yield improvement. Subsequent investigations unveiled a paraneoplastic syndrome secondary to breast cancer. Discussion: Diagnosing these clinical entities is challenging due to their multifaceted presentations, often leading to delayed identification, increased patient suffering, economic burdens, and preventable complications. Conclusion: Anti-amphiphysin-associated meningoencephalitis is a rare manifestation of paraneoplastic syndromes. It is crucial to raise awareness among healthcare professionals about the diverse presentations of paraneoplastic syndromes.