This study is a retrospective, non-interventional and, post-authorization observational study of other designs (PAS-OD).
This multicenter trial will be conducted in Spain. Retrospective review of medical records and initial tumor biopsies of participants diagnosed with PTCL in the period of 6 years between 01/01/2008 and 31/12/2013 will be performed. Initial tumor biopsies and histological preparations, filed and previously anonymized, will be sent to the central laboratory for assessment.