Neuropsychiatric profiles of patients with insulinomas

Insulinoma is a rare and potentially curable disease. It is often misdiagnosed as neurological or psychiatric disorder. This study was performed to characterize the neuropsychiatric symptoms (PNS) of the patients with insulinoma from a regional clinical center.

All medical records of the patients with histopathologically identified insulinoma were reviewed during the period from 1998 to 2008. A case-control analysis was performed to compare the demographic data, details of clinical presentation, biochemical findings, tumor localization, and intraoperative findings between the patients with and without a prior misdiagnosis.

Among 42 patients with insulinoma, 25 patients with PNS were initially misdiagnosed as having a neurological or psychiatric disease, while 17 patients with no PNS were correctly diagnosed. Most (64%) of PNS cases were not diagnosed correctly until 12 months after the first consultation. In patients with PNS that remained undiagnosed for at least 5 years, the most frequent symptoms were confusion, convulsion, and visual disturbances. Twelve cases of PNS were initially misdiagnosed as epilepsy and 3 of them showed epileptiform discharges on electroencephalography.

Episodic hypoglycemia induced by insulinoma can greatly mimic neurological and psychiatric presentation. A thorough history taking and inpatient assessment are necessary in evaluating recurrent neurological and psychiatric symptoms.