Subacute cerebellar degeneration as paraneoplastic syndrome: initial symptom of breast cancer with HER2 overexpression.

We report the case of a patient with subacute cerebellar degeneration presenting as paraneoplastic syndrome, preceding the final diagnosis of breast cancer. The tumor had high HER2 overexpression, so a weekly regimen of paclitaxel/trastuzumab was started after surgery of the primary breast tumor. Negativity of specific antineuronal antibodies and clinical stabilization of the patient was achieved after 12 cycles of treatment. The interest of this case is the unusual presentation and the targeted therapeutic approach that has been used.