Ectopic insulin secreting neuroendocrine tumor of kidney with recurrent hypoglycemia: a diagnostic dilemma

BMC Endocrine Disorders

Table 1 Insulin secreting extra-pancreatic tumors reported in literature

Case		Evidence of hyperinsulinemia^ain tumour	Resolution of hypoglycemia after resection of tumour	Evidence of neuro-endocrine origin	Mechanism of hypoglycemia -proposed
1	Ovarian carcinoid [5]	Insulin staining (5%), EM – beta cell granules, absence of pancreatic tumor at autopsy	Not demonstrated	HPE	Direct tumoral secretion of insulin
2	Carcinoma cervix [6]	Insulin staining, absence of pancreatic tumor at autopsy	Not demonstrated	HPE	Liver metastasis^b, Direct tumoral secretion of insulin
3	Bronchial carcinoid [7]	Insulin staining	Not demonstrated	HPE	Liver metastasis^c, Direct tumoral secretion of insulin
4	Paraganglioma [8]	None	Yes	HPE	No conclusive evidence of direct tumoral secretion of insulin
5	Paraganglioma [9]	Insulin staining (3%)	Yes	HPE	Direct tumoral secretion of insulin
6	Pheochromocytoma [10]	Insulin stain negative, absence of pancreatic tumor at autopsy	Not demonstrated	HPE	Beta adrenoceptor mediated release of insulin from pancreas
7	Neuroendocrine tumor of liver [11]	Insulin staining, absence of any extrahepatic tumor at autopsy, Selective arterial calcium stimulation	Not demonstrated	HPE	Direct tumoral secretion of insulin^d
8	Neuroendocrine tumour kidney (carcinoid) (present case)	Insulin staining, EM – beta cell granules,	Yes	HPE, 68Gallium DOTANOC, HYNICTOC imaging	Direct tumoral secretion of insulin

^aIncludes evidences other than biochemical documentation of hyperinsulinemia in critical samples(collected at the time of hypoglycemia).
^bLiver functions are reportedly normal in this patient.
^c70% of the liver was replaced by tumor at autopsy in this patient.
^dThis patient developed hypoglycemia after left hepatectomy.
HPE – Histo-pathological examination, EM – Electron Microscopy.

ISSN: 1472-6823