Needle Tract Seeding: An Overlooked Rare Complication of Endoscopic Ultrasound-Guided Fine-Needle Aspiration.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been widely used for diagnosis of both inflammatory and tumor lesions located in and adjacent to the gastrointestinal tract. EUS-FNA has been considered to be a safe technique with few complications, as shown in recent review articles in which EUS-FNA-related morbidity and mortality rates were reported to be <1%. It should be noted, however, that needle tract seeding, although uncommon, can occur after diagnostic EUS-FNA and that this complication affects the prognosis of patients. Although an accurate value for the frequency of needle tract seeding caused by EUS-FNA has not been reported, the numbers of case reports on needle tract seeding have been rapidly increasing, especially in Japan. These case reports regarding EUS-FNA-related needle tract seeding prompted us to reevaluate the safety of EUS-FNA because this complication may have a significant influence on patients' prognoses. In this review, we summarize the clinical features and outcomes of needle tract seeding after EUS on the basis of the previously reported cases and provide useful information to prevent and reduce this serious complication.