Extrathyroidal implantation of thyroid tumor cells after needle biopsy and other invasive procedures

Background: Implantation of thyroid cells (ITC) into extrathyroidal locations is a rare complication of thyroid fine-needle biopsy (FNB) and thyroid surgery. Here we review the prevalence, likely pathogenesis, treatment, and likely ways to minimize this complication of invasive thyroid procedures and present an illustrative patient. Summary: Tumor aggressiveness more likely leads to ITC after FNB. Large needle size may be associated with increased risk of ITC. Number of passages during biopsy, excessive suction, needle withdrawal without releasing suction, and injection of tumor cells during biopsy may be associated with ITC after FNB. This statement is based on rational hypotheses. Cutting or rupture of a thyroid nodule during surgery leads to ITC into extrathyroidal soft tissue. Conclusions: ITC occurs rarely with needles smaller than 23 gauge. Some authorities suggest the use of gentle suction and release suction during extraction and a reduced number of passes based on entirely theoretical grounds. In conventional surgery, lobectomy for all thyroid nodules rather than nodulectomy or partial lobectomy should be performed. If endoscopic surgery is performed on larger nodules, the surgeon should take great care to avoid rupturing the tumor.