Sugiyama Toru, Kouyama Ryuji, Tani Yuji, Izumiyama Hajime, Akashi Takumi, Kishimoto Seiji, Arii Shigeki, Hirata Yukio
Department of Clinical and Molecular Endocrinology, Tokyo Medical and Dental University Graduate School.
Intern Med. 2010;49(15):1573-9. doi: 10.2169/internalmedicine.49.3540. Epub 2010 Aug 2.
Insulinomas are the most common hormone-producing pancreatic neuroendocrine tumors (NETs), which are usually benign, solitary and small. We describe herein a patient with a giant insulinoma (>10 cm in diameter) with concomitant thyroid tumor as detected by Somatostatin receptor scintigraphy (SRS). A 50-year-old man presented hypoglycemic symptoms 20 years after the first detection of a pancreatic tumor, which was ameliorated by administration of a somatostatin analogue, octreotide. SRS showed abnormal uptake by the insulinoma as well as by the thyroid tumor. RT-PCR and immunohistochemical study revealed abundant expression of somatostatin receptor (SSTR)-1, -2, and -5 in his insulinoma and SSTR-1 and -2 in his thyroid follicular neoplasm. This is a rare case of a slow-growing pancreatic well-differentiated neuroendocrine carcinoma over a long period of time to become a symptomatic giant insulinoma. Furthermore, SRS proves to be a useful tool for localization of insulinoma as well as concomitant thyroid neoplasm with predominant expression of SSTRs.
