[Peduncular hallucinosis associated with a space occupying lesion of the brain stem]

Traditionally visual hallucinations have been divided into simple and complex. Complex hallucinations due to disorder of the brainstem have been described, and this process referred to as peduncular hallucinosis.

A 74 year old woman with a history of endometrial carcinoma with metastases to bones and lungs, was admitted for progressive ataxia and paraesthesias of the left half of her body. During her admission to hospital she had complex visual hallucinations of cartoon animals, animals, people and geometrical figures. The patient herself realized that they were hallucinations. On cerebral computerized tomography there was a space occupying lesion in the pons-midbrain region of the brainstem. In the clinical context of this particular patient, it was considered to probably be a metastasis from the carcinoma of the endometrium.

Apart from its theoretical interest, peduncular hallucinosis has well defined stereotyped characteristics, and recognition of these may be useful in topographical diagnosis of the lesion.