Definition der kritischen Größe eines klinisch symptomatischen Insulinoms - eine retrospektive Studie

In the period from 1997 to 2020, 65 patients with the diagnosis of insulinoma presented themselves at the university hospitals Marburg and Mainz and the tumors were systematically documented and evaluated as part of this study. With an incidence of 1- 4/1.000.000 per year, insulinoma is a rare neuroendocrine neoplasm, which is why the set of data analyzed in this work is relatively large. The primary objective of this study was to determine a possible correlation between the volume and the clinical symptoms or laboratory values of the documented insulinomas. Based on this, the aim was to define a critical cell mass from which an insulinoma shows clinical symptoms. The thesis confirmed that large insulinomas are associated with increased secretion patterns. Tumor sizes above the median or in upper quartile correlated with significantly heightened insulin concentrations, especially when the fasting test was discontinued and the blood sugar measured was lowest. In addition, it was demonstrated that insulinomas with a maximum diameter of 6.0 mm or a volume of 0.1 cm3 became clinically symptomatic. The values of the 2.5th percentile were also used as limits for the occurrence of symptoms and read as follows: 6.6 mm and 0.1 cm3. No data was found in the previous literature that could be used for comparison with the study results obtained. Furthermore, the described benign and malignant insulinomas were compared in terms of their secretion patterns. The sample included 57 benign and 9 malignant neoplasms. In patients suffering from a malignant tumor, the lowest blood sugar measured showed a significantly higher insulin concentration than in those with benign neoplasms. Secondary, there was a significantly higher C-Peptide concentration in relation to malignant insulinomas when the fasting test was stopped. Additionally, the extremely rare case of proinsulinomatosis was documented as part of this study. This is a proinsulin-secreting form of insulinomatosis which is characterized by the synchronous and metachronous occurrence of insulinomas and their precursor lesions. In the literature to date there is no reported case of proinsulinomatosis.