Etiological Spectrum and Pattern of Change in Pituitary Stalk Thickening: Experience in 321 Patients

Objective: To summarize the etiologies of pituitary stalk thickening (PST) and the natural course of indistinguishable PST. Methods: Clinical information, including the symptoms at onset and laboratory, imaging, operative, pathological, and follow-up data, of patients with MRI-confirmed PST at Peking Union Medical College Hospital from January 2014 to May 2017 was collected and reviewed. Results: Of 321 eligible patients with PST, 28.3% were <18 years old. Central diabetes insipidus was the initial symptom in 68.8% of patients. At least one anterior pituitary hormone deficit was found in 57.6% of patients. The adjusted OR of panhypopituitarism associated with hypothalamus involvement was 7.3 (95% CI, 3.0 to 17.8; P < 0.001). Confirmed diagnoses were established in 137 patients (42.7%), including neoplasms (75.2%), inflammation (13.1 %), and congenital anomalies (11.7%). Intracranial germ cell tumors (66.7%) were the leading cause among children, whereas histiocytoses (20.0%) and malignant metastases (14.7%) were the most common causes in adults. Thirty-eight patients with indistinguishable PST underwent a second MRI at a median time of 4.4 months. Spontaneous remission was observed in 17 of these patients (44.7%) after a median 8.5 months, with complete remission in 14 (36.8%) and partial remission in three (7.0%); five (13.2%) patients exhibited progression, and the remaining 16 (42.1%) stabilized. Conclusion: PST is highly heterogeneous, and most confirmed cases are attributed to neoplasms. The etiological spectrum varies with age. Physicians must be familiar with the major differential diagnoses, necessary investigations, and follow-up. Biopsy is indicated when radiological progression and/or worsening of pituitary function is detected.