Subclinical Needle Tract Seeding by Endoscopic Ultrasound-Guided Fine-Needle Aspiration for Pancreatic Cancer

A 77-year-old woman with epigastralgia was referred to our hospital. Abdominal computed tomography showed a hypointense mass in the pancreatic tail. Abdominal and endoscopic ultrasonography (EUS) showed a hypo-echoic mass, 25 x 25 mm in size, with pancreatic duct dilatation. EUS-guided fine-needle aspiration (EUS-FNA) was performed to the mass through gastric posterior wall. Pathological examination showed atypical cells growing papillary or tubular fashion, leading to the diagnosis of adenocarcinoma. Under the preoperative diagnosis of T2N0M0 pancreatic cancer, the patient underwent distal pancreatectomy and splenectomy. Macroscopic view of the resected specimen showed a presumed puncture-induced pancreatic pseudocyst adjacent to the pancreas. Pathological examination showed well-differentiated adenocarcinoma and a pseudocyst with presumed migrated atypical cells in the pseudocyst wall. The patient recovered uneventfully and has been on outpatient follow-up with adjuvant TS-1 therapy. Optimal treatment of pancreatic cancer naturally needs preoperative definitive diagnosis more strictly than other solid malignancies due to its much higher operative harm to the patients. EUS-FNA is a safe and effective diagnostic method but needs careful attention to the needle tract seeding.