Mediastinal Pseudocyst Associated with Chronic Pleural Effusions

Abstract

To the Editor: We read with great interest the article by Zeilender et al (Chest 1990; 97:1014-16) on mediastinal extension of a pancreatic pseudocyst presenting as a chronic pleural effusion. We recently were faced with a similar case and had the same concern about how to proceed in treating the cyst in a patient who was not a surgical candidate. A 55-year-old black man was admitted to District of Columbia General Hospital with a 2-week history of dyspnea, nonproductive cough, and weight loss. Despite a strong history of ethanol abuse, he denied any prior history or symptoms of pancreatitis. The initial chest x-ray film demonstrated a large left pleural effusion and a small right pleural effusion. The left effusion was hemorrhagic with an elevated amylase concentration of 3,230 Somogyi units. The serum amylase concentration was 66 Somogyi units. Pleural biopsy was negative for acid-fast bacilli and malignancy. The right pleural effusion was transudative with an amylase concentration of 46 Somogyi units. The patient underwent tube thoracostomy and drainage of the left pleural effusion. A subsequent computed tomographic (CT) scan of the chest and abdomen showed a posterior mediastinal cystic mass with extension into the abdominal cavity, suggesting the diagnosis of a mediastinal pseudocyst. Conservative management with hyperalimentation was attempted; however, 5 weeks later the patient developed Staphylococcus aureus bacteremia and hemodynamic instability necessitating the administration of vasopressors. We proceeded with CT-guided percutaneous catheter drainage of the intra-abdominal cyst, which resulted in concurrent drainage of the thoracic cyst. After initial improvement, the patient's condition deteriorated over the ensuing 4 weeks. Candidemia developed, and the patient eventually died. This case demonstrates an alternative approach to that of Zeilender et al to a patient who is not a surgical candidate if conservative therapy and hyperalimentation are not effective. Often, CT-guided drainage of the abdominal cyst will also result in drainage of the thoracic component and clinical improvement. There have been two previous reports documenting this technique in the management of complications arising from a mediastinal pancreatic pseudocyst.1Faling LJ Gerzof SG Daly BDT Pugatch RD Snider GL Treatment of chronic pancreatitic pleural effusion by percutaneous catheter drainage of abdominal pseudocyst.Am J Med. 1984; 76: 329-333Abstract Full Text PDF PubMed Scopus (12) Google Scholar, 2Semelka RC Greenberg HM Percutaneous drainage of an infected mediastinal pseudocyst.J Can Assoc Radiol. 1987; 38: 54-55Google Scholar Our case underscores several points in the approach to these patients. First, although a history of pancreatitis or abdominal trauma can be elicited in most cases, symptoms relating to the pleural effusion may be the sole manifestation of pancreatitis.3McKenna JM Craig RM Chandrasekhar AJ Cugell DW Skorton D. The pleuropulmonary complications of pancreatitis.Chest. 1977; 71: 197-204Crossref PubMed Scopus (34) Google Scholar Second, the elevated fluid amylase concentration was the first clue to the diagnosis; therefore, the amylase level should be determined routinely in evaluation of chronic effusions. Some reports suggest that a pleural fluid amylase value significantly higher than the simultaneous serum value is pathognomonic for a pancreatogenic effusion.4Kaye MD Pleuropulmonary complications of pancreatitis.Thorax. 1968; 23: 297-306Crossref PubMed Scopus (109) Google Scholar, 5Dewan NA Kinney WW O'Donohue WJ Chronic massive pancreatic pleural effusion.Chest. 1984; 85: 497-501Crossref PubMed Scopus (30) Google Scholar To a lesser degree, this can also be seen in some malignant effusions. Third, we concur that CT is a sensitive tool in confirming the diagnosis.