Von Hippel-Lindau disease presenting as pancreatic neuroendocrine tumour.

A 21-year-old woman with a family history of von Hippel-Lindau disease presented with a mass in the head of the pancreas. Light microscopic features of the tumour suggested neuroendocrine differentiation and although it displayed positive immunostaining for the antigens expected in a neuroendocrine neoplasm, S-100 staining was also present. This unusual feature prompted further evaluation by routine and post-embedding protein-A gold immunoelectron microscopy, which demonstrated the presence of neuroendocrine granules. Tumour cell DNA content was normal by flow cytometry. Although this patient exhibited no other signs of von Hippel-Lindau disease, the presence of a pancreatic tumour with neuroendocrine differentiation demonstrated that she was affected. Future surveillance and genetic counselling will be influenced by this diagnosis.