Rapid-onset paraneoplastic cerebellar degeneration successfully treated by radiotherapy and tumorectomy.

We report the first-ever documented case of successful treatment of paraneoplastic cerebellar degeneration (PCD) with radiotherapy. A 31-year-old female presented with rapidly progressing neurological symptoms, which were revealed to be due to PCD secondary to an undiagnosed breast cancer. The cancer responded well to chemotherapy, but her neurological status continued to deteriorate, eventually progressing to complete expressive aphasia and dyssynergia with paraparesis. Due to the extraordinarily rapid progression of the disorder, a treatment with tumorectomy and radiotherapy of the whole brain was performed. This proved to be very successful, with a complete stop of the deterioration of symptoms after treatment and with a significant neurologic improvement in the following months. This case indicates that there may be a place for radiotherapy in the treatment of PCD. Current treatment options have proven insufficient and no guidelines for treatment currently exist. As such, the disorder remains associated with a very poor prognosis and often entails permanent loss of function. Radiation, with its known immunosuppressive effect and non-stochastic effects on the nervous system at the proper doses, might therefore be a valid option. However, we should note that it was in this instance combined with a removal of the primary tumor and as such, its individual efficacy cannot be considered proven.