Aims
Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare low-grade malignant neoplasm. SPN with prominent atypical multinucleated giant tumor cells (MNGTCs) has not been reported.
Methods and results
We identified four cases of SPN with prominent atypical MNGTCs in a cohort of 62 cases of SPN (6.5%). The MNGTCs contained multiple enlarged, hyperchromatic, irregular nuclei with ample eosinophilic cytoplasm, typically present in the solid area of the tumor. The MNGTCs had a typical immunohistochemical profile of the conventional SPN and were positive for vimentin, β-catenin, CD10, and progesterone receptor, but were negative for pan-cytokeratin chromogranin, synaptophysin, trypsin, Ki-67 and CD68 in all four cases. Patients of SPN with prominent MNGTCs were older than those with conventional SPN (p=0.01), tumors were incidentally discovered by imaging studies for an unrelated disease in all four cases, and with a female to male ratio of 1:1. The proliferation index (Ki-67) was <1% in all four cases. None of the three patients, whose follow up information was available, developed recurrence during follow-up of 2.7, 3.8 and 5.0 years.
Conclusions
The presence of MNGTCs in SPN most likely represents degenerative change of the tumor cells and does not seem to affect the prognosis.