Incidental diagnosis of diffuse large B-cell lymphoma by 11C-choline PET/CT in a patient with biochemical recurrence of prostate cancer.

The main indication for C-choline PET/CT in prostate cancer patients is the early localization of biochemical recurrence after radical treatment. However, any C-choline uptake should be assessed in terms of physiological distribution and patterns of tumor spread. Therefore, tracer-avid lesions in unexpected sites should be carefully addressed because the diagnosis of other malignancies has important therapeutic implications. We present a patient with biochemical recurrence of prostate cancer treated with radiotherapy. C-choline PET/CT showed local recurrence and inguinal lymph node uptake. Because of its location beyond typically prostatic lymphatic spread, resection was performed. Histology confirmed a diffuse large B-cell lymphoma.