Circulating Tumor DNA Sequencing in Patients With Peripheral T-cell Lymphomas

Inclusion Criteria: * Aged 18 or over * Newly diagnosed or relapsed/refractory peripheral T-cell lymphoma (PTCL), including T/NK lymphoma (NKTL) * Pre-therapeutic FDG PET-CT already performed * Signed informed consent * Patients affiliated with or beneficiaries of a health insurance plan Exclusion Criteria: * Cutaneous T-cell lymphomas without systemic involvement * Pregnant or breastfeeding women * For newly diagnosed patients: patient who has already started the first systemic treatment for their lymphoma (apart from pre-phase corticosteroid therapy which is authorized) * For patients in a relapsed/refractory situation: Patient who has already started the new specific line of lymphoma treatment planned for the current relapsed/refractory situation (apart from pre-phase corticosteroid therapy which is authorized) * Lack of patient consent * Patient whose weight is less than 30 kg * Protected adult or deprived of freedoms (under guardianship or curatorship) * Patient unable to understand the study for any reason or to comply with the constraints of the trial (language, psychological, geographic problem, etc.).