Isolated Port-Site Recurrence after Laparoscopic Distal Pancreatectomy for Pancreatic Adenosquamous Carcinoma: A Case Report.

INTRODUCTION: Minimally invasive pancreatectomy has become widely adopted worldwide. However, its oncologic safety in malignant diseases remains a matter of ongoing debate, including atypical patterns of tumor recurrence. Port-site recurrence (PSR) is a rare but clinically relevant condition following minimally invasive oncologic surgery. Although several mechanisms, including tumor manipulation and pneumoperitoneum-related factors, have been proposed, the underlying pathogenesis remains unclear. Especially in pancreatic cancer, reports of PSR after minimally invasive surgery are extremely limited, and its optimal management has not been established. CASE PRESENTATION: A 75-year-old man was referred to our institution with a pancreatic tail tumor detected on CT during evaluation of epigastric pain. Contrast-enhanced CT and endoscopic US-guided fine-needle aspiration biopsy led to a diagnosis of pancreatic cancer, and laparoscopic distal pancreatectomy was performed as upfront surgery. Intraoperatively, no peritoneal dissemination was observed, and peritoneal cytology was negative. The pancreatic tail tumor demonstrated invasion of the anterior pancreatic serosa. Histopathological examination revealed adenosquamous carcinoma composed of approximately 70% squamous cell carcinoma and 30% adenocarcinoma components. The postoperative course was uneventful, and adjuvant chemotherapy with S-1 was administered. Approximately 6 months after surgery, the patient developed a painful mass at the left lower trocar site. Contrast-enhanced CT and abdominal ultrasonography revealed a 3 × 4-cm irregular mass within the rectus abdominis muscle at the corresponding trocar site, with no evidence of distant metastasis. The lesion was considered an isolated PSR based on multidisciplinary discussion, and surgical resection was performed. Intraoperative findings confirmed the absence of peritoneal dissemination, and the tumor was completely resected. Pathological examination revealed metastatic squamous cell carcinoma, consistent with the squamous component of the primary tumor, leading to a diagnosis of PSR. The patient remains free of recurrence 6 months after resection. CONCLUSIONS: PSR after minimally invasive surgery for pancreatic cancer is extremely rare. In this case, tumor biology, especially the squamous component in adenosquamous carcinoma, may play a key role in its development. Surgical resection may be considered in carefully selected patients with isolated PSR, although further studies are required to clarify its clinical significance.