We report a 53-year-old man presenting with a sore throat, chest pain, and dysphagia. We diagnosed phlegmonous esophagogastritis. Contrast-enhanced CT revealed diffuse thickening of the esophagus and stomach wall with an intramural low-density area surrounded by peripheral rim enhancement. On postcontrast CT, the cranial side of the abscess was continuous with the pharyngeal submucosa, suggesting the source of the inflammation. Upper gastrointestinal endoscopy demonstrated purulent material draining from esophageal and gastric ulcers. Acute phlegmonous esophagogastritis is a rare disorder characterized by diffuse infiltration of inflammatory cells to the submucosa of the esophagus and stomach. Detecting a connection of esophageal lesion with the pharynx may lead to a better clinical assessment of the disease.