Thyroid metastasis from intraductal papillary-mucinous carcinoma of the pancreas. A case report

BACKGROUND: Intraductal papillary-mucinous carcinoma (IPMC) of the pancreas is a newly identified clinicopathologic entity of the exocrine pancreas. It has been considered a slowly growing and less-aggressive carcinoma with a favorable prognosis. There have been only a few documents reporting its distant metastasis and cytologic features, with no report of thyroid metastasis until the present. CASE: A case of IPMC occurred in a 45-year-old male, who was admitted with rapid growth and tenderness of the thyroid. Abdominal computed tomography showed the typical cystic dilatation of IPMC with adjacent organ metastasis. Fine needle aspiration of the thyroid yielded papillary fronds of carcinoma cells with nuclear pleomorphism, abundant cytoplasm and prominent nucleoli in a mucinous background. Immunohistochemical findings from the skin and thyroid characterized the papillary-mucinous carcinoma as having originated in the pancreas. CONCLUSION: This case suggests that papillary carcinoma fronds aspirated from the thyroid should be further differentiated from the primary site and that a pleomorphic nucleus in a mucinous background is a useful feature to exclude a thyroid origin. Before this, distant metastasis of IPMC to the skin and thyroid has not been reported. The prognosis of IPMC with wide, distant metastasis at an advanced stage is poor.