Pancreatic Pseudocyst With Thoracic Extension: A Clinicoradiological Case Report.

Pancreatic pseudocysts are encapsulated, enzyme-rich peripancreatic fluid collections that typically develop following acute or chronic pancreatitis due to pancreatic ductal disruption. While commonly localized to the lesser sac, rare mediastinal extension may occur, presenting with nonspecific thoracic symptoms such as chest pain, dyspnea, or dysphagia. Cross-sectional imaging (CT/MRI) is essential for diagnosis. Management is individualized, ranging from conservative medical therapy to endoscopic, percutaneous, or surgical drainage based on symptom severity, complications, and anatomical considerations. We report the case of a 26-year-old male with a history of alcohol use and smoking, presenting with cough and dyspnea. Clinical examination revealed tachypnea, hypoxia, and signs of right-sided pleural effusion. Chest X-ray revealed complete opacification of the right hemithorax. Diagnostic thoracentesis yielded amylase-rich pleural fluid (11,545 IU/L). Serum amylase and lipase were also elevated. Contrast-enhanced CT imaging demonstrated acute necrotizing pancreatitis with peripancreatic collections extending into the thoracic cavity via the esophageal hiatus, confirming a pancreatic pseudocyst with secondary massive right-sided amylase-rich pleural effusion. The patient was managed conservatively with antibiotics, octreotide, and ultrasound-guided pigtail catheter drainage. The clinical course was favorable, with complete symptomatic resolution and no evidence of recurrence on follow-up. This case underscores a rare but significant thoracic complication of acute pancreatitis manifesting as massive pleural effusion, mimicking thoracic pathology. Thus, accurate diagnosis using contrast-enhanced CT and MRCP, along with tailored management from conservative therapy to invasive drainage, is crucial. Early recognition and multidisciplinary care ensure favorable outcomes, as highlighted in this case.