Goals: To assess the characteristics and prognosis-influencing factors of phlegmonous esophagitis, a rare condition marked by suppurative inflammation of the esophageal submucosa and muscular layers. Background: Effective management strategies for phlegmonous esophagitis are lacking. This study aims to systematically review cases to better understand the disease’s features and prognostic determinants. Method: A systematic search was performed using PubMed/MEDLINE and Google Scholar from inception to 20 April 2023. Phlegmonous esophagitis case reports and studies with patient information were included; clinical manifestations, laboratory results, imaging findings, other diagnostic findings, and outcomes were analyzed. A pooled analysis was performed to investigate mortality-related risk factors. Results: A total of 35 cases of phlegmonous esophagitis were selected from 31 case reports and 2 case series (median age, 57.0 years; male, 54.3%). The patients presented various clinical symptoms, with neck-to-epigastric pain and dysphagia being the most common. Comorbid diabetes mellitus was a major predisposing factor; one-third of the patients had no previous medical history. Computed tomography (CT) and endoscopic examinations were predominantly used for phlegmonous esophagitis diagnosis. Radiological findings showed that the upper and middle esophagus were most frequently involved. Treatments included administration of broad-spectrum antibiotics and drainage via endoscopy or surgery. There were three cases of mortality, and non-survivors tended to have shorter hospital stays, indicating rapid disease progression. In logistic regression, thoracic surgery was a significant mortality-related risk factor (odds ratio, 19.30; 95% confidence interval, 1.33–282.00, p = 0.03). Conclusion: Advancements in CT and endoscopy have led to less-invasive diagnostic and treatment methods for phlegmonous esophagitis. Endoscopic localized abscess treatment is associated with positive outcomes.