Papillary cystic tumours of the pancreas: an analysis by nuclear morphometry.

Papillary cystic tumour (PCT) is a rare, low-grade malignant pancreatic neoplasm, in which the histological criteria for malignancy are still uncertain. We performed a histological examination of 3 metastasizing PCTs, while comparing them with 18 non-metastasizing PCTs, using a computed image analyser. The mean maximum nuclear diameter, the mean standard deviation (SD) of the nuclear diameter, the mean nuclear area and the nuclear-nonnuclear (N/NN) ratio obtained by the image analyser of the metastasizing PCTs (7.23 microns, 2.21 microns, 30.45 microns2, 36.41%) were all significantly larger than those of the non-metastasizing PCT (6.34 microns, 1.59 microns, 23.66 microns2, 23.74%; P < 0.005, P < 0.005, P < 0.005, P < 0.001 respectively). However, there were no statistical differences in either the nuclear ellipsoidity or nuclear regularity. These results suggested that nuclear morphometry might be a useful parameter to define metastatic potential, in addition to histological variables such as venous invasion, nuclear grade and mitotic rate.