FNA is particularly useful in documenting a metastatic malignancy involving the pancreas.
- Lung carcinoma (small cell and squamous cell)
- Breast carcinoma
- Non-Hodgkin lymphoma
- Renal cell carcinoma
Because ductal cell adenocarcinoma is by far the most common pancreatic tumor, any aspirate showing cytologic features unusual for this diagnosis should raise the possibility of a metastasis. Although distinctive cytologic features may suggest the primary site, most cases require immunohistochemical stains and a thorough clinical history.