An insulinoma is a neuroendocrine tumor derived from pancreatic islet cells responsible for the secretion of exaggerated amounts of insulin. Consequently, they induce recurrent states of hypoglicemia and manifest clinically with a wide range of symptoms including confusion, behavioral disturbances and impaired consciousness.

To report a case of a patient with an insulinoma presenting with neuropsychiatric symptoms.

To highlight the diagnostic difficulties of medical or surgical disorders presenting with clinical features overlapping psychiatric syndromes.

Review of the scientific literature and the patient's clinical notes.

A 68-year old male, with a previous history of depressive episode, was admitted to the psychiatric ward following behavioral disturbances and neuropsychiatric symptoms with the provisional diagnosis of “depressive episode with hypochondriac features”. Despite some overall improvement with antidepressants and antipsychotics, unremitting episodes of weakness, sweating, tachycardia, palpitations associated with hypoglicemia were apparent. Complementary workup disclosed hyperinsulinism and a pancreatic insulinoma. Following surgical ablation of the tumor, the patient improved dramatically from the neuropsychiatric symptoms.

Neuropsychiatric symptoms are a common clinical presentation of an insulinoma. A high level of clinical expertise is crucial to avoid that patients are misdiagnosed with psychiatric illnesses before insulinoma is recognized.