ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR PRIMARY MEDIASTINAL LARGE B‐CELL LYMPHOMA PATIENTS RELAPSING AFTER HIGH DOSE CHEMOTHERAPY WITH AUTOLOGOUS STEM CELL TRANSPLANTATION: DATA FROM THE JAPAN SOCIETY FOR HEMATOPOIETIC CELL TRANSPLANTATION (JSHCT) REGISTRY. (12th June 2019) - Kondo, E.