The presence of multiple pancreatic cysts is a rare finding, particularly in the absence of other polycystic changes indicative of adult polycystic kidney disease (renal cysts and liver cysts are almost ubiquitous prior to pancreatic cyst development). The remaining differential for multiple pancreatic multiple cysts is extremely limited. This might include postinflammatory cysts which are usually associated with some form of acute or chronic inflammatory finding. Multiple intra papillary mucinous neoplasms could be considered, however, these are usually multilocular side branch communicating lesions. In the absence of cystic lesions elsewhere, the appearances are almost certainly due to von Hippel-Lindau (VHL) syndrome.
VHL syndrome is associated in approximately 50% of cases with pancreatic cysts, representing the sole focus of disease of approximately 10% of cases. The precise incidents of cysts varies from family to family with VHL. The majority of these cases are asymptomatic. Cysts can replace the entirety of the pancreas, rarely associated with exocrine dysfunction. The cysts are commonly simple cysts or can reflect a unilocular/oligocystic serous cystadenomas. Serous (microcystic) cystadenomas can also occur in their polymicrocystic configuration with central scarring or calcification. Unlike the cystic lesions of the kidney in VHL these lesions have no malignant potential. Mucinous cystic lesions do not occur in VHL.
In addition to simple cysts and serous cystadenoma a third type of lesion can occur in the pancreas in VHL. This is the presence of neuroendocrine lesions appearing and 8-17% of cases. In this case the enlarged diffusely arterially enhancing lesion in the head the pancreas indeed reflects an additional neuroendocrine tumour. Neuroendocrine lesions in VHL are ubiquitously nonfunctioning, however, have a propensity to malignancy. Despite this predisposition to malignancy they are less likely to metastasize than comparable nonfunctioning neuroendocrine tumours in patients without VHL (10-20% v 60-90%).
Criteria have been proosed (Blansfield et al) for projection of metastatic risk in pancreatic neuroendocrine tumour in patients with VHL. These include tumour size greater or equal to 3 cm, the presence of mutation in exon 3 and a tumour doubling time of <500 days. If the patient has none of these criteria the risk of metastatic disease is considered low and radiological surveillance is advised every 2-3 years, if 1 criterion is positive follow-up every 6-12months is advised. If 2 or more criteria are positive surgical management should be considered due to higher risk of future neuroendcrine malignancy.