Inclusion Criteria:  All consecutive patients treated in the centre during the period considered Age>=18 years Histological diagnosis of PMBCL Signature of "Informed Consent" to participate in the study (if applicable) Treatment according to local practice Diagnosis between 01 January 2007 and 31 December 2019  Exclusion Criteria:  - The exclusion criteria, being an observational study, are focused and limited to excluding cases with a non-compliant histological diagnosis.