Detection of thyroid carcinoma in wall of a cystic lesion by FDG PET.
OBJECTIVE
Three cases are described, in which positron emission tomography (PET) led to the diagnosis of carcinoma in solitary thyroid nodules (STN), which were considered benign by clinical assessment, ultrasonography, and fine needle aspiration cytology (FNAC).


METHODS
These 3 cases were from a group of 51 patients with solitary thyroid nodules that were nonfunctioning or "cold" on pertechnetate scans that were later studied with FDG PET scanning.


RESULTS
Of the entire group, 28 patients showed the nodule to be nonfunctioning on FDG scans. Of these, 3 showed one or more small foci of intense FDG uptake in the periphery. On histopathology, these sites were found to harbor carcinoma, papillary carcinoma in 2 patients and a follicular variant of papillary carcinoma in one.


CONCLUSIONS
These cases demonstrate the usefulness of FDG PET in detection of cancer that may lurk in the wall of a cystic thyroid nodule, often misinterpreted as benign by conventional methods.
Nair
Narendra
N
Radiation Medicine Centre, Tata Memorial Hospital, Mumbai, India.
Agrawal
Archi
A
Nayak
U N
UN
D000328:Adult; D002277:Carcinoma / Q000175:diagnosis / Q000000981:diagnostic imaging*; D003560:Cysts / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D016606:Thyroid Nodule / Q000175:diagnosis / Q000000981:diagnostic imaging*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18