Metastatic tonsillar squamous cell carcinoma masquerading as a pancreatic cystic tumor and diagnosed by EUS-guided FNA.

Metastatic carcinoma to the pancreas is uncommon and head and neck squamous carcinoma metastatic to the pancreas is extremely rare. Metastatic squamous cell carcinoma to the pancreas presents a unique diagnostic challenge: in addition to mimicking the rare primary squamous cell carcinoma of the pancreas based on cytologic, histologic, and immunohistochemical features, it may be mistaken for a cystic neoplasm of the pancreas because of its high predilection for cystic degeneration in metastatic sites. Herein, we report a case of tonsillar squamous cell carcinoma with a cystic pancreatic metastasis diagnosed by ultrasound-guided fine needle aspiration biopsy (EUS-FNA). This represents a third reported case of metastatic squamous cell carcinoma to the pancreas from the head and neck region. Metastatic squamous cell carcinoma should be considered in the differential diagnosis of EUS-FNA during evaluation of pancreatic cystic lesion.