Endocrine Abstracts

Background: MEN-1 is a rare disease characterized by parathyroid adenoma or hyperplasia, pituitary adenoma and pancreatic neuroendocrine tumors (PNET). Gastrinomas are the most common functional PNET in MEN-1 disease. Insulinomas and glucagonomas constitute approximately 20 and 3% of PNET’s in MEN-1 disease. Most of insulinomas are benign in nature but about 70% of cases of glucagonomas present with metastasis at diagnosis. Coexistence of various PNET’s are very rare entity in MEN-1 disease.

Case: A 27-years-old female presented with loss of consciousness and headache during fasting. Neurological and physical examination was normal. Her laboratory findings were consistent with insulinoma and primary hyperparathyroidism. Prolonged fasting test was consistent with insulinoma. A 0.4 cm pituitary mass was found on MRI which was non-functional. Tc 99 m sestamibi SPECT/CT demonstrated a lift lower parathyroid adenoma. There was not pancreatic mass on USG, CT and MRI. EUS demonstrated a 0.9 cm mass in distal pancreas. EUS guided FNAB was consistent with PNET. The patient underwent parathyroid adenomectomy and thymectomy followed by distal pancreatectomy. Histopathological analysis of distal pancreas demonstrated three well-differentiated PNET. Immunohistochemical analysis was positive for glucagon and negative for insulin in the largest tumor (0.8 cm), and positive for insulin but negative for glucagon in remaining two tumors (0.6 and 0.5 cm). All of three tumors were strongly positive for chromogranin and synaptophysin and negative for somatostatin. After surgery, glycemia became immediately normal.

Conclusion: Very small number of the coexistent double small insulinoma along with a small glucagonoma in MEN-1 disease have been reported in English literature. However, insulinoma could be multifocal and could also be associated with glucagonoma, as in the present case. Small tumors could be missed easily on pathologic analysis, therefore, careful histopathological examination of pancreas should be made in cases of MEN-1 disease