Pneumatosis cystoides intestinalis (PCI) is a rare clinical pathology characterized by sub-mucosal and/or sub-serous cysts of free gas, forming cystic lesions usually ranging from 0.5 to 2.0 cm in size within the gastrointestinal tract. About 3% of patients with PCI develop complications such as pneumoperitoneum, intestinal volvulus, obstruction, or hemorrhage, these cases need immediate surgical intervention. Cyst rupture can produce peritoneal irritation and pneumoperitoneum.A 65-years-old woman was admitted to the Emergency Department for epileptiform convulsions. Her medical hystory included epilepsy, diabetes, lichenoid dermatitis, hypothyroidism, severe cognitive impairment. Abdominal CT scan revealed a dilated large intestine with parietal pneumatosis from the appendix to the transverse colon associated to extensive pneumoperitoneum. The patient underwent emergency laparotomy which revealed the presence of gas within the wall of right and transverse colon and distension of great omentum. No resection was needed as normal blood supply to the bowel present.Pneumatosis coli can be both asymptomatic or life-threatening condition associated to bowel infarction; this situation can mimic a bowel perforation causing pneumoperitoneum - that sometimes is a non-surgical pneumoperitoneum - and it could be a misleading indication to surgical exploration especially in the case of uncertain origin of a septic shock.We report a case of pneuomoperitoneum due to PCI. Surgical intervention was required for patient's conditions and unclear origin of the sepsis.