misinterpretation of an inflammatory fdg uptake in a patient treated for hodgkin lymphoma: a case report

Hodgkin lymphoma (hl) is a malignancy involving lymph nodes and lymphatic system. [18f]f-fdg pet/ct (fdg-pet) imaging is routinely used for staging, to assess early chemotherapy response (interim fdg-pet), at the end of treatment (eot fdg-pet) and for the identification of disease recurrence.we present a case of a 39-year-old man treated for hl. fdg-pet scans performed after first line therapy (both interim pet and at the end of therapy) demonstrated a persistent and significant mediastinal fdg uptake. the patient was treated with a second line therapy but the fdg-pet uptake did not change. after board discussion a new surgical, thoracoscopy-guided biopsy was performed. histopathology demonstrated a dense fibrous tissue with occasional chronic inflammatory infiltrates.persistent fdg-pet positivity may suggest refractory or relapsed disease. however, occasionally, non-malignant conditions are responsible for a persistent fdg uptake, not related to primary disease. an accurate evaluation of clinical history and previous imaging exams is mandatory for clinicians and others experts to avoid misinterpretations of fdg-pet results. nevertheless, in some cases, only a more invasive procedure, such as a biopsy, may finally lead to a definitive diagnosis.