Reporting terminology

Diagnostic terminology for pancreatic FNA uses a five-tier system including the following categories:

• Negative for malignant cells
• Atypical cells present
• Suspicious cells present
• Positive for malignant cells
• Non-diagnostic specimen

A negative diagnosis in the setting of a radiologically detected mass implies either a failure to sample the lesion or the presence of a benign process such as chronic pancreatitis. An ‘atypical’ diagnosis reflects a mild degree of cytologic atypia, often in the setting of inflammation. This interpretation implies a low suspicion of malignancy. A diagnosis of suspicious cells present implies a strong suspicion of malignancy, but the cytologic features are insufficient for a definite diagnosis.

The non-diagnostic category is used when lesional tissue was not obtained or the cells are obscured beyond interpretation; it is accompanied by an explanation, such as obscuring inflammation or blood, air-drying artefact, or insufficient cellularity. Although no adequacy criteria exist for pancreatic FNA, a non-diagnostic interpretation due to the lack of epithelial cells may also be appropriate in the setting of cysts and pseudocysts. When the imaging and cytologic features suggest either a mucinous cystic neoplasm or an intraductal papillary mucinous neoplasm, without definite features of malignancy, the most appropriate diagnosis is ‘consistent with a mucinous cystic (or an intraductal papillary mucinous) neoplasm’.