A Rare Mimicker of Achalasia

Pancreatic pseudocyst in posterior mediastinum is very rare complication of acute or chronic pancreatitis. They are caused by rupture of the pancreatic duct posteriorly into the retroperitoneal space and track through the diaphragmatic hiatuses into the mediastinum. Mediastinal pancreatic pseudocyst should be suspected in a patient presenting with atypical chest pain, dyspnea, or dysphagia, in the setting of a clinical history of pancreatitis. A 22-year-old female presented with complaint of dysphagia for both solids and liquids along with retrosternal discomfort, regurgitation and significant weight loss of 6 kgs (15% of body weight) since last 3 months. She had history of recurrent acute pancreatitis since childhood. Over a period of time, she was diagnosed to have chronic calcific pancreatitis and pseudocyst 2 years back. Physical examination was unremarkable expect for mild epigastric tenderness. Routine blood investigations were within normal limits. UGI endoscopy showed dilated esophagus with fluid stasis with smooth tapering at the distal end, scope passed with difficult across seeming of achalasia cardia. But subsequently CECT abdomen showed features of chronic calcific pancreatitis and thin walled well-defined hypodense fluid collection along the esophageal hiatus into the posterior mediastinum. The fluid collection is seen around the OG junction and approximately 5 cm length of lower esophagus causing significant luminal compression and resultant proximal dilatation of thoracic esophagus. EUS showed large pseudocyst 6.5 cm × 5.5 cm in the mediastinum abutting cardiac chamber and aorta with wall thickness of 2 mm. MRCP showed features of pancreatic pseudocyst with pancreatic duct disruption. Hence ERCP been planned after esophageal dilation using CRE balloon up to 13.5 mm to allow passage of the ERCP scope. Pancreatogram showed dilated PD with leak (communication with the cyst at the tail region). A single PD stent deployed. Subsequently she was discharged in stable condition with advise to continue PERT, PPI, and antioxidant. After 2 months patient symptoms were completely subsided and the pseudocyst seen along the esophageal hiatus in previous CT was completely resolved. Unlike other pancreatic pseudocyst, mediastinal pseudocyst does not get resolve by own. High index of suspicion required for diagnosis. Multimodal approach is necessary for treatment. The literature was reviewed for clinical presentations and available treatment options for mediastinal pancreatic pseudocysts.