Pneumoperitoneum Secondary to Necrotic Intra-abdominal Lymph Node

Pneumoperitoneum is often treated as a surgical emergency as the most common etiology is perforated hollow viscus. Here, we present the case of a man in his 70s who presented to the emergency department with fever and abdominal pain. On physical exam, he was diffusely tender in the bilateral lower quadrants with guarding. Imaging demonstrated moderate volume pneumoperitoneum. On review of his imaging, the pneumoperitoneum was centered around a 7 cm necrotic lymph node. Repeat CT scan with positive oral (PO) and rectal contrast demonstrated no extraluminal contrast extravasation, but air bubbles were seen extending from the necrotic lymph node into the lower abdominal cavity. He underwent CT-guided drain placement and was started on antibiotics, and improved without surgical intervention. In stable patients presenting with pneumoperitoneum and known intra-abdominal lymphadenopathy, perforated viscus should be ruled out prior to surgical intervention, and necrotic intra-abdominal lymph node should be considered as a differential diagnosis.