Cause:Neoplastic adenoma; or a nodule of multinodular goiter (PLUMMER'S DISEASE)
Pathophys:Only 5% will be "hot," producing T3T4 and toxic sx but that guarantees benign pathology
Present in 4-8% of US adult population by physical exam, <5% malignant; up to 50% over age 50 yr have 1 by ultrasound; in 20-30% of irradiated adult population 10-30 yr later, ~10% of which are malignant and 1/2 of those detectable by physical exam (Ann IM 1981;94:176; Nejm 1976;294:1019). Male/female = 1:4
Cancer in 5-10% of cold nodules by biopsy studies; increased incidence in the young and males
Lab:
Chem:TSH to r/o thyrotoxicosis from toxic nodule, so get scan if TSH low, otherwise go to path
Path:Fine needle aspiration bx to r/o cancer (Ann IM 1993;118:282); 90% sens/specif (Ann IM 2005;143:926)
Xray:
123I scan only useful if aspiration cytology is suspicious/intermediate because can avoid surgery if nodule is hot (functioning)
Ultrasound especially to guide needle aspiration or f/u of neg nodules
Rx:
Medically follow (Ann IM 1998;128:386); if incr in size, do fine needle bx; if benign, put on suppression rx and watch another year, although long-term consequences of suppression now being questioned (Ann IM 2005;143:926); if incr in size again, surgically excise.
of hot nodule, 131I rx to control hyperthyroid sx; but 25% develop myxedema at 5 yr and 20% stay as big or get bigger (Nejm 1983;309:1473), so may need surgery eventually anyway