Histological findings in patients with suspected mediastinal lymphoma relapse according to positive positron emission tomography scan during follow-up: a large retrospective analysis in 96 patients.

Residual masses in patients with mediastinal lymphoma may be positron emission tomography (PET) positive during follow-up also in cases of complete response. The aim of this retrospective study is to verify the reliability of mediastinal PET-positive findings in suggesting disease relapse or progression during follow-up by histological verification. From January 2002 to March 2016, 96 patients with mediastinal lymphoma underwent PET follow-up after front-line treatment. A surgical biopsy was performed to confirm the suspected relapse (for a total of 113 procedures). A lymphoma relapse was diagnosed in 66/102 successful procedures (64.7%). Diagnosis at relapse was concordant with the initial diagnosis in all but 3 cases. Standardized uptake value was significantly higher among patients with relapse than among those who remained in remission (10 versus 5,