Checkpoint inhibitors and radiotherapy in refractory malignant melanocytic schwannoma with Carney complex: first evidence of efficacy

Abstract

Melanocytic schwannoma (MS) is a rare nerve sheath tumour characterised by melanin-producing neoplastic schwann cells that typically affects the posterior spinal nerve roots. We report an ultrarare case of recurrent/metastatic MS associated with Carney complex in a young woman with family history of breast cancer. This highlights the novel approach of combined checkpoint inhibitors (CPI) and radiotherapy. The patient was initially treated with Nivolumab along with concurrent external beam radiotherapy. There was sustained clinical benefit achieved for over 15 months with preserved quality of life. Addition of Ipilimumab, which she tolerated reasonably well, helped to control the progressive disease again for another 12 months. She harboured a rare PRKAR1A R228 mutation (Carney complex) and received appropriate targeted therapy. She survived for 51 and 35 months from her initial diagnosis and start of CPI, respectively, which to the best of our knowledge is the longest documented survival in this rare entity.