53 year old man, known case of carcinoma rectosigmoid colon, stage 3C. He was operated a year ago. PETCT done for re-staging.
In the neck, there was a 1cm focal calcified lesion in the posterior mid pole right lobe of thyroid gland, associated with intense FDG uptake (SUV max 8.5).
In the pelvis, there was an irregular soft tissue attenuation mass in the presacral space, measuring 2.0 x 3.0 x 5.8cm in size, associated with intense FDG uptake (SUV max 8.4).
A diagnosis of tumour recurrent in the presacral space of pelvis & thyroid incidentaloma was made.
Focal increased FDG uptakes in the thyroid are called incidentalomas. They are found in about 2-3% of healthy individuals. However, focal thyroid incidentalomas found on FDG PET done for cancer staging may have a high prevalence of thyroid malignancy. Possibilities are either follicular carcinoma or thyroid metastases.