Cushing's syndrome from ectopic production of corticotropin by a metastatic gastrinoma.

OBJECTIVE

To present a case of a young woman with new-onset diabetes mellitus resistant to insulin attributable to Cushing's syndrome caused by ectopic production of corticotropin by a metastatic gastrinoma.

METHODS

We summarize the clinical presentation and the pertinent laboratory values in a patient with Cushing's syndrome. A review of the literature regarding ectopic production of corticotropin by gastrinomas is also presented.

RESULTS

A 26-year-old woman with dehydration, severe hyperglycemia, and hypokalemia was seen in consultation. The patient required large doses of insulin to control plasma glucose, and further work-up confirmed the presence of Cushing's syndrome caused by ectopic production of corticotropin from a metastatic gastrinoma.

CONCLUSION

This case is unusual in that the patient was relatively young and the clinical presentation of Cushing's syndrome was dominated by uncontrolled diabetes, insulin resistance, and hypokalemia. At the time of this diagnosis, the patient already had evidence of multiple liver metastatic lesions from a pancreatic gastrinoma. The rapid occurrence of difficult-to-treat diabetes and hypokalemia should raise the suspicion of Cushing's syndrome from ectopic production of corticotropin. In fact, patients with metastatic pancreatic tumors and poorly controlled diabetes with hypokalemia should undergo evaluation for Cushing's syndrome, even in the absence of the typical stigmas, because of rapid development of the disease and high levels of corticotropin.