Diffusely increased thyroidal uptake of F-18 fluorodeoxyglucose in a patient with non-Hodgkin's lymphoma and Graves’ disease
A 63-year-old female patient with non-Hodgkin's lymphoma in remission for the last 2 years after chemotherapy was referred to our department for a whole body FDG-positron emission tomography (PET)/computed tomography scan to assess for disease recurrence after recent onset of diplopia and raised β2-microglobulin levels. Multiple lymph nodes in the cervical, mediastinal and right axillary regions showed increased metabolic activity, suggestive of recurrence. In addition, diffusely increased FDG uptake was seen in both lobes of the thyroid gland on the whole body PET image [], with a standardized uptake value of 12.3. On clinical examination, she was found to have bilateral exophthalmos and the biochemical profile showed high T3 and T4 and low thyroid stimulating hormone values, suggestive of hyperthyroidism. Subsequently, a 99mTcO4 (pertechnetate) scan [], also showed diffusely increased tracer uptake in the thyroid gland; uptake at 20 min was 6.1%. A diagnosis of Graves’ disease was made and treatment with Carbimazole was started.