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Case Reports
. 2021 Aug 7;13(8):e16969.
doi: 10.7759/cureus.16969. eCollection 2021 Aug.

Microsatellite Instability-High, Malignant Insulinoma With Brain Metastasis

Jason Starr  1 , Guillermo Puebla  2 , Jessica McMillan  3 , Jason T Lewis  4 , Pashtoon M Kasi  5
Affiliations
Case Reports

Microsatellite Instability-High, Malignant Insulinoma With Brain Metastasis

Jason Starr et al. Cureus. .

Abstract

Insulinomas are the most common type of functional pancreatic neuroendocrine tumor. Although insulinomas usually are noninvasive or benign, 10% are deemed invasive or malignant. The pathologic mechanisms that lead to the malignant phenotype are not well elucidated. In this case report, we present a patient with stage 4 malignant insulinoma with metastasis to the liver, bone, and brain. Genetic analysis of the tumor showed that the tumor was mismatch-repair deficient and had a high rate of microsatellite instability. There was loss of MLH1- and PMS2-encoded protein expression, and MLH1 and MEN1 variants were identified. Notably, the liver metastasis showed considerable tumor heterogeneity (well differentiated) compared with the brain metastasis (poorly differentiated).

Keywords: cancer-immunotherapy; men 1; msi- high; pancreatic insulinoma; pancreatic neuroendocrine tumors.

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Conflict of interest statement

Pashtoon M. Kasi: Advisory/Consultancy: •Taiho Oncology (to institution) •Ipsen (to institution) •Natera •Foundation Medicine •Merck •AstraZeneca •Bayer •Daiiche Sankyo (AZ) •Delcath Pashtoon M. Kasi: Research/Trial Support (to institution) •BMS •Celgene •Astrazeneca •BTG/Boston Scientific •Advanced Accelerator Applications •Array Biopharma •RenovoRx •Amgen •Tersera •Seagen •Roche/Genentech

Figures

Figure 1
Figure 1. Magnetic resonance imaging (coronal) shows a pancreatic tail mass (red arrow), liver metastasis (blue arrow), and retroperitoneal lymphadenopathy (asterisk).
Figure 2
Figure 2. Liver, well-differentiated neuroendocrine tumor (hematoxylin-eosin, original magnification x 200).
Figure 3
Figure 3. Liver, Ki-67 immunohistochemical stain (original magnification x 400). The proliferation rate was estimated to be 30%.
Figure 4
Figure 4. 68Gallium DOTATATE positron emission tomography−computed tomography imaging (axial) of the brain shows a right parietal lesion and left frontal lesion.
Figure 5
Figure 5. 68Gallium DOTATATE positron emission tomography−computed tomography imaging (axial) shows a pancreatic tail lesion (red arrow).
Figure 6
Figure 6. Brain, poorly differentiated neuroendocrine tumor (hematoxylin-eosin, original magnification x 400).
Figure 7
Figure 7. Brain, Ki-67 immunohistochemical stain (original magnification x 400). The proliferation rate was estimated to be 90%.
Figure 8
Figure 8. MLH1, weakly positive (+1).
Figure 9
Figure 9. PMS2, absent.
Figure 10
Figure 10. MSH2, positive (+2).
Figure 11
Figure 11. MSH6, positive (+2).
See this image and copyright information in PMC

References

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