Intense focal F-18 FDG uptake in vocal cord associated with injection of calcium hydroxylapatite microspheres.

Lower F-18 fluorodeoxyglucose (FDG) uptake on PET/CT is generally expected on the side of a paralyzed vocal cord (VC). The contrary pattern of increased uptake can raise concern for metastasis or a primary VC malignancy. We present a case showing paradoxical development of intense FDG uptake in the paralyzed VC, unrelated to malignancy. History revealed injection of calcium hydroxylapatite microspheres for treatment of VC paralysis. This new synthetic material can stimulate local fibroblast activity and macrophage accumulation, leading to increased FDG uptake. The case illustrates the importance of obtaining accurate history before interpreting intense FDG uptake in a paralyzed VC.