Acute complete deafness with rhombencephalitis in a breast cancer survivor: a rare association

Abstract Background Rhombencephalitis is an inflammatory condition involving the pons, medulla, and caudal midbrain. It is often attributed to infectious or autoimmune etiologies. Paraneoplastic brainstem encephalitis is rare and is most commonly associated with cancers such as small-cell lung cancer or ovarian cancer. Non-metastatic neurological manifestations of breast cancer are uncommon, and breast cancer has not previously been reported to predispose patients to rhombencephalitis with diverse neurological dysfunctions. Case presentation In this report, a 43-year-old Egyptian female who had a mastectomy three years ago presented with eight days of worsening hearing problems on both sides, which turned to total deafness, with facial muscle paralysis on both sides, dysfunctional oculo-vestibular movements, ataxia in the trunk, and bulbar signs. She did not have a fever, and infection tests yielded negative results. Blood tests found leukocytosis and other abnormalities, while CSF found marked albuminocytologic dissociation, with elevated protein and glucose levels, but not pleocytosis or cancer cells. Brain MRI showed extensive T2/FLAIR hyperintensity involving the pons, medulla, and midbrain. MRS revealed NAA and choline were normal, arguing against demyelinating or neoplastic processes. Cervical spine MRI excluded longitudinally extensive transverse myelitis. Conclusion This case shows a unique paraneoplastic rhombencephalitis presentation in a patient with past breast cancer. Neurologists should maintain heightened clinical vigilance for such presentations.