Masked diabetes insipidus in pituitary metastasis from breast cancer after thalamic biopsy: a case report.

BACKGROUND: Symptomatic pituitary metastasis is rare; furthermore, it can result in diabetes insipidus and panhypopituitarism. Since diabetes insipidus is masked by concurrent panhypopituitarism, it can impede the diagnosis of pituitary dysfunction. CASE PRESENTATION: A 68-year-old Japanese female suffering from pituitary and thalamic metastases caused by untreated breast cancer, underwent a biopsy targeting the thalamus, not the pituitary. She lacked prebiopsy pituitary dysfunction symptoms; however, these symptoms unexpectedly occurred after biopsy. Diabetes insipidus was masked by corticosteroid insufficiency, and she showed normal urinary output and plasma sodium levels. Upon commencement of glucocorticoid replacement therapy, the symptoms of diabetes insipidus appeared. CONCLUSIONS: In this case, thalamic biopsy, as opposed to pituitary biopsy, was performed to preserve pituitary function. However, pituitary dysfunction could not be avoided. Caution is necessary for asymptomatic patients with pituitary metastases as invasive interventions, such as surgery, may induce pituitary dysfunction. Moreover, with respect to masked diabetes insipidus, there is a need to carefully consider pituitary dysfunction to avoid misdiagnosis and delayed treatment.

Bilateral pallidal stimulation for cervical dystonia. An optimal paradigm from our experiences.

We sought to identify optimal paradigms of bilateral globus pallidus internus (GPi) stimulation in 3 subsequent patients with severe cervical dystonia. At low frequency stimulation (50-60 Hz) with wide pulse width (500 micros) and high amplitude (4.5-8.0 V), we observed immediate and consistent improvement of dystonia and dystonia-associated pain. Stimulation of the posteroventral portion of the GPi led to pronounced alleviation of dystonia; stimulation of the anterodorsal portion or at the dorsal border of the GPi resulted in significant worsening of symptoms. The therapeutic benefit obtained by using the optimal stimulation parameters continues and has lasted for at least 1 year in each patient.