Cytomorphologic observations on the sclerosing variant of well-differentiated pancreatic neuroendocrine tumors: Towards making specific diagnoses early.

The hypocellular nature of spNET cytology samples makes this variant difficult to diagnose. However, when adequate sample is available, a subset of spNET show characteristic cytomorphology that enables us to consider this specific diagnosis at first diagnostic sampling. It is crucial to diagnose this variant early given the propensity of small tumors with regional lymph node involvement and liver metastases.