Non-Interventional Management of Advanced Pancreatic Neuroendocrine Neoplasms in Patients with von Hippel-Lindau Disease

Hereditary Syndromes Associated with Pancreatic and Lung Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PanNETs) and lung NETs (LNETs) represent a rare but clinically significant subgroup of neoplasms. While the majority is sporadic, approximately 17% of PanNETs and a subset of LNETs develop in the context of monogenic familial tumor syndromes, especially multiple endocrine neoplasia type 1 (MEN1) syndrome. Other inherited syndromes associated with PanNETs include MEN4, von Hippel-Lindau (VHL) syndrome, neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC). These syndromes are highly penetrant and their clinical manifestations may vary even among members of the same family. They are attributed to genetic mutations involving key molecular pathways regulating cell growth, differentiation, and angiogenesis. Pancreatic NETs in hereditary syndromes are often multiple, develop at a younger age compared to sporadic tumors, and are associated with endocrine and nonendocrine tumors derived from multiple organs. Lung NETs are not as common as PanNETs and are mostly encountered in MEN1 syndrome and include typical and atypical lung carcinoids. Early detection of PanNETs and LNETs related to inherited syndromes is crucial, and specific follow-up protocols need to be employed to optimize diagnosis and management. Genetic screening is recommended in childhood, and diagnostic screening starts often in adolescence, even in asymptomatic mutation carriers. Optimal management and therapeutic decisions should be made in the context of a multidisciplinary team in specialized centers, whereas specific biomarkers aiming to identify patients denoted to follow a more aggressive course need to be developed.

Diversities of Mechanism in Patients with VHL Syndrome and diabetes: A Report of Two Cases and Literature Review

Background

Von Hippel-Lindau (VHL) syndrome is characterized by tumorous lesions affecting multiple organs. Pancreatic involvement in VHL syndrome can present as endocrine tumors and pancreatic cysts, which can interfere with both exocrine and endocrine functions of the pancreas. Diabetes is an uncommon complication of VHL syndrome.

Purpose

This study aims to summarize the various mechanisms of diabetes in VHL syndrome by reporting two cases and conducting a literature review.

Methods

We analyzed the clinical and imaging data of two patients with VHL syndrome and diabetes. Additionally, we reviewed the existing literature to explore the clinical diversities and management strategies for VHL syndrome complicated with diabetes.

Results

The first patient presented with liver metastasis of pancreatic neuroendocrine tumor and multiple pheochromocytoma. After surgery, the patient's diabetic control improved, as evidenced by a significant reduction in insulin dosage. This indicates a potential insulin resistance due to elevated metanephrine levels prior to surgery and partial insulin deficiency caused by distal pancreatectomy. The second patient had multiple hemangioblastomas, as well as multiple pancreatic cysts and positive pancreatic islet autoantibodies. Diabetes in this case may be attributed to pancreatic lesions and the coexistence of autoimmune insulitis. A literature review of other patients with VHL combined with diabetes revealed multiple mechanisms, including increased catecholamine levels, pancreatic lesions, surgical removal of pancreatic tissue, endocrine treatment, and possibly the coexistence of autoimmune insulitis.

Conclusion

VHL syndrome complicated with diabetes involves diverse mechanisms.

[Multiple neuroendocrine tumors of the pancreas]

Multiple neuroendocrine tumors (NET) of the pancreas often have a hereditary background. Sporadic and hereditary NET do not differ morphologically or with regard to their hormone expression. The most important clues for a hereditary background are provided by examination of the peritumoral pancreatic tissue, especially the morphology and hormone expression of the endocrine islets. Hyperplastic or dysplastic islets and microtumors with aberrant distribution of insulin and glucagon are the main features of hereditary NET. Morphological diagnosis of potentially hereditary NET has a relevant impact on the prognosis and clinical care of patients.