Unusual Presentation of Pneumoperitoneum Caused by Adenocarcinoma of the Pancreas Penetrating the Descending Colon Associated with Splenic Abscess

Background: Although pancreatic cancer is frequently locally aggressive, initial presentation as pneumoperitoneum is atypical. We report a case of ruptured spleen probably due to direct invasion of pancreatic cancer to descending colon presenting as peritonitis and pneumoperitoneum. Methods: We examined the case of a woman who presented to our emergency department with acute abdominal pain associated with intra-splenic gas lesion. Results: A 67-year-old woman was admitted to our department after three weeks of fever and left back pain. After discovering a splenic abscess via computed tomography (CT), antibiotics were administered and surgery was planned. On post-admission day four, she presented sudden diffuse abdominal pain, displaying muscle guarding and rebound tenderness. Abdominal CT demonstrated a pneumoperitoneum and intra-abdominal fluid around the spleen. A splenectomy, left hemicolectomy, lymph node dissection, and transverse colostomy were performed. The resected specimen presented a fistula from spleen to descending colon and perforation of splenic abscess. Histopathological and immunohistochemical examination demonstrated that pancreatic adenocarcinoma had infiltrated to the colon. The patient discharged on 22 days after surgery, and multiple metastases with liver and sacral bone was diagnosed after 36 days from discharge. Conclusion: Since intra-splenic gas lesion following with pneumoperitonitis can be caused by many disorders, prompt recognition and early diagnosis help clinicians determine an appropriate management strategy.