Thickened but unclear: Clinical course of isolated pituitary stalk thickening in the pediatric age group

Abstract Background The incidence of pituitary stalk thickening (PST) has increased in recent years due to the increased utilization of diagnostic MRI of the brain. The clinical significance of PST, appropriate diagnostic workup, and clinical course for these patients is not well documented. Methods After Institutional Review Board approval, we reviewed the pediatric tumor board and pediatric endocrinology clinic records between 2003 and 2024 to identify patients with PST. We followed the clinical course of these patients to collect applicable data. Results A total of 29 patients were identified with PST; 11 were excluded due to additional MRI findings, and out of 18 selected patients, 9 were females (50%). Initial diagnostic workup included complete blood count (CBC), basic metabolic panel, serum and cerebrospinal fluid (CSF) tumor markers (AFP, β-hCG), and skeletal survey. With the initial workup, no patient was diagnosed with neoplasm. Patients were followed with serial MRIs. Five patients (27.7%) displayed progression of PST, warranting biopsy (2 germinomas, 2 Langerhans cell histiocytosis, and 1 inconclusive). The median time to biopsy was 8 months (range 4-26 months). All the patients diagnosed with neoplasm had central diabetes insipidus at presentation, and 3 went on to develop additional endocrine abnormalities. Ten patients had stable PST over a median follow-up period of 19 months (range 0-81 months), and 3 patients had complete resolution of PST during the follow-up period. Conclusion Most isolated PST among pediatric patients remain stable over time. Serial monitoring of patients with isolated PST can be safe, and not all cases of PST warrant upfront biopsy.