Hyperinsulinemic hypoglycemia associated with ectopic Cushing's syndrome due to a pancreatic endocrine tumor in a Type 2 diabetes mellitus patient: clinical implications of a rare association.
BACKGROUND
The coexistence of insulin and ACTH hypersecretion in the same patient is extremely rare. A diabetic patient with a pancreatic endocrine tumor (PET) co-secreting insulin and ACTH is even rarer and has never been described. The combination of these two endocrine syndromes results in a peculiar clinical picture.


OBJECTIVE
To determine the cause of glycemic variations in a patient with previously stable diabetes mellitus.


METHODS
This is a clinical case report from the Endocrinology Unit of Aosta Hospital and Internal Medicine and Surgical Unit of Verona University. A 69-yr-old diabetic patient was hospitalized for recurrent severe hypoglycemic events persistent after withdrawal of anti-diabetic drugs. The causes of hypoglycemia and subsequent resumption of hyperglycemia were investigated.


RESULTS
An insulin-secreting PET was diagnosed. Diazoxide and octreotide therapy initially was able to control hypoglycemic symptoms, then, a Cushing's syndrome occurred resulting in worsening of diabetes control. ACTH was found to be released by the PET previously diagnosed as an insulin-secreting tumor. The tumor was removed and the histology was consistent with a well differentiated endocrine carcinoma. After surgery, adrenal function was normal and insulin therapy was again necessary to control diabetes.


CONCLUSIONS
A single PET may be responsible for both a hyperinsulinemic and a Cushing's syndrome. When this rare association occurs, each of the two syndromes may affect the other resulting in a peculiar clinical course. Finally, an insulin-secreting PET has to be kept in mind as a rare cause of hypoglycemia in diabetic patients.
Filippella
M
M
SC Internal Medicine Unit of Diabetology and Endocrinology, Parini Hospital, Aosta, Italy.
Davì
M V
MV
Doveri
G
G
Lillaz
E
E
Ciccarelli
A
A
Massimetti
E
E
Toaiari
M
M
Falconi
M
M
Colao
A
A
Faggiano
A
A
D000182:ACTH Syndrome, Ectopic / Q000209:etiology* / Q000473:pathology / Q000601:surgery; D000368:Aged; D003480:Cushing Syndrome / Q000150:complications* / Q000209:etiology* / Q000601:surgery; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D006801:Humans; D006946:Hyperinsulinism / Q000209:etiology*; D007003:Hypoglycemia / Q000209:etiology*; D007340:Insulinoma / Q000150:complications* / Q000473:pathology / Q000601:surgery; D008297:Male; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
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