Background <p>Pneumatosis cystoides intestinalis(PCI) is a relatively rare condition with a pathogenesis that remains incompletely understood. It is typically managed through conservative medical treatment, with surgical intervention considered when necessary. We report a case of PCI in which the lesions resolved spontaneously after diagnostic endoscopic submucosal dissection (ESD).</p> Case presentation <p>A 51-year-old female, who had resided long-term at high altitude, presented with persistent abdominal pain and increased bowel movements. Routine blood tests and biochemical profiles showed no significant abnormalities. Colonoscopy revealed multiple submucosal protrusions in the ascending colon, which firm on probing with biopsy forceps. Endoscopic ultrasound demonstrated hyperechoic with acoustic shadowing. In combination with findings from contrast-enhanced abdominal CT, ESD was performed to remove one of the larger protrusions. Pathological examination confirmed the diagnosis of PCI. More than two years later, follow-up colonoscopy and contrast-enhanced abdominal CT revealed complete resolution of the lesions. Notably, the patient had not received any treatment during this period, aside from a change in her place of residence.</p> Conclusions <p>This case illustrates a rare but clinically important presentation of colonic PCI mimickingfirm subepithelial lesions, with documented complete resolution on both colonoscopy and CT after relocation from a high-altitude region.</p>