[Endocrine carcinoma of the pancreas revealed by a pseudocyst]

Pancreatic pseudocysts are the most frequent cystic lesions of the pancreas. They always are associated with acute or chronic pancreatitis. We here report the case of a pseudocyst of the pancreas associated with obstructive chronic pancreatitis and diagnosed in a 47-year-old man without previous history of acute pancreatitis and without risk factor. The examination of the surgical specimen resulted in the incidental discovery of an obstructive nodule of endocrine carcinoma, measuring 9 mm in diameter and located immediately at the contact of the pseudocyst. The tumor was ill limited and associated with metastatic spread in 2 peripancreatic lymph nodes. Immunohistochemical studies showed that 60% of tumor cells expressed serotonin. This case report underlines that the diagnosis of pseudocyst must be done much cautiously in patients without a clinical history of pancreatitis and without risk factor. In most cases, the lesion corresponds to a misdiagnosed cystic tumor. Even if the lesion actually corresponds to a pseudocyst, as in the present case, an unusual cause, and particularly, an obstructive tumor, must be searched for.