18F-Choline PET/CT as a New Tool for Functional Imaging of Non-Proliferating Secreting Neuroendocrine Tumors
Abstract
Choline is an essential component for the formation of new cell membrane and the current understanding is that increased choline uptake in cancer lesions is explained by - and roughly correlates with - cellular proliferation.18F-fluoromethylcholine, a radiolabeled PET-tracer, is increasingly used for the detection of proliferating cancers with PET/CT (choline PET), for example for restaging of recurrent prostate carcinoma. However, clinical findings have suggested that choline uptake may not always be related to proliferation. We present three cases with a carcinoid of the lung with high uptake of radiolabeled choline on PET/CT and a low Ki-67 proliferation index as demonstrated by immunostaining. Although the mechanism behind the enhanced uptake in well-differentiated neuroendocrine tumors is not yet fully understood, for clinical practice this finding means that not every highly choline-avid lesion represents an aggressive cancer; the diagnosis of a functional neuroendocrine tumor should be considered as well.
J Endocrinol Metab. 2015;5(4):267-271
doi: http://dx.doi.org/10.14740/jem300w