Intraoperative Cytodiagnosis for Detecting a Minute Invasion of the Portal Vein during Pancreatoduodenectomy for Adenocarcinoma of the Pancreatic Head

During pancreatoduodenectomy for adenocarcinoma of the pancreatic head, we frequently encountered cases in which the superior mesenteric-portal venous confluence (SMPVC) was involved with cancer. With regard to the indication of the concomitant SMPVC resection, as suggested by recent papers, a better long-term outcome would be expected if the cancer invasions were limited to the tunica adventitia or media of the SMPVC wall. Since this raised fears whether such a small SMPVC invasion was always detectable by macroscopic inspection alone, we have performed an intraoperative cytology on the touch smear of the exposed SMPVC wall for 23 patients with pancreatic head cancer. All of their SMPVCs were separated from the pancreatic head and appeared to be intact at a macroscopic level. As a result of the cytologic examination, however, 7 patients (30%) were newly diagnosed as having cancer cells on the SMPVC wall, and they received an additional resection of the SMPVC. Postoperative histology indicated that cancer invasion into the SMPVC wall was present in 6 of the 7 patients, and that the cancer invasions were limited in the tunica adventitia in 5 patients and to the tunica media in 1 patient. Thus, in order not to miss the chance of cure by SMPVC resection, our intraoperative cytology on the touch smear of the SMPVC is worth performing more actively on the macroscopically intact-looking SMPVC during resection of pancreatic cancer.