Pneumatosis cystoides intestinalis (PCI) is the term for the formation of intramural gas filled cysts of unclear pathogenesis in the wall of the gastrointestinal tract. We report two patients with PCI where the diagnosis was confirmed by endoscopic puncture of a lesion, resulting in a complete deflation of the cyst, and two patients who underwent surgery. Endoscopy offers a safe and quick way to confirm the diagnosis of PCI. The immunohistochemical study revealed histiocytic cells and foreign body giant cells in the cystic wall, corresponding to a secondary histiocytic organization of gas-filled pseudocysts rather than to the widespread theory of gas-filled lymph vessels.