Pitfall of 18F-FDG PET/CT in Characterization of Relapsed Multisystem Lymphomatoid Granulomatosis.

We present serial 18F-FDG PET/CT findings in a case of grade 3 pulmonary lymphomatoid granulomatosis positive for the Epstein-Barr virus. The patient experienced a transient complete response to R-CHOP chemotherapy and subsequent multisystem recurrence, predominately involving the subcutaneous region of the torso on 18F-FDG PET/CT. Biopsy of the most hypermetabolic subcutaneous lesion demonstrated grade 1 cutaneous lymphomatoid granulomatosis negative for the Epstein-Barr virus. This report highlights the role of 18F-FDG PET/CT in characterizing and monitoring disease progression and regression, as well as the limitations of 18F-FDG PET/CT in accurate grading of multisystem recurrence, given the diversity of clinical and histopathologic features of lymphomatoid granulomatosis.