Pituitary Stalk Enlargement in Adults

Area of Science:

• Endocrinology
• Neurology
• Radiology

Background:

• Pituitary stalk (PS) pathologies often present with diabetes insipidus.
• Magnetic resonance imaging (MRI) aids in lesion visualization, but enlarged PS without a clear lesion poses diagnostic challenges.
• Direct pituitary stalk biopsy is invasive and often inconclusive, necessitating indirect etiological diagnosis.

Purpose of the Study:

• To review literature on adult pituitary stalk enlargement.
• To differentiate between various etiologies and their diagnostic approaches.
• To guide the etiological diagnostic procedure for enlarged pituitary stalks.

Main Methods:

• Literature review of pituitary stalk enlargement in adults.
• Systematic search for systemic lesions via CT scans, positron emission tomography, and bone scans.
• Measurement of serum markers including human chorionic gonadotropin, alpha-fetoprotein, angiotensin converting enzyme, and IgG4.

Main Results:

• Metastatic carcinoma, histiocytosis, sarcoidosis, and tuberculosis are key differential diagnoses for PS enlargement.
• Isolated PS enlargement may be monitored with MRI, with germinoma considered in young adults.
• Spontaneous lesion diminution suggests infundibulo-neurohypophysitis, while progression may indicate histiocytosis or germinoma.

Conclusions:

• Etiological diagnosis of pituitary stalk enlargement often relies on indirect evidence and systemic investigations.
• Monitoring is crucial, especially for isolated PS enlargement, with biopsy reserved for specific indications.
• A prolonged surveillance strategy is recommended due to potentially delayed progression of certain pathologies.