Endocrine Abstracts

Introduction: Thickened pituitary stalk (TPS) and/or idiopathic central diabetes insipidus (ICDI) are rare in childhood, presenting to different (endocrine, oncology, ophthalmology) specialties. In the absence of other diagnostic features, agreed radiological definitions, biopsy (often too dangerous) or consensus management guidance, subsequent surveillance and treatment are uncertain. Cases may remain undiagnosed or evolve over decades.

Aims: i) To longitudinally characterize a large childhood cohort presenting with TPS and/or ICDI, ii) to identify any underlying occult pathology over a long follow-up, iii) to assess clinical, visual and endocrine correlates over time.

Methods: We searched the terms ‘thickened pituitary stalk’ or ‘idiopathic diabetes insipidus’ in electronic radiology and clinical document libraries at our split-site centre (UCLH/GOSH) over the last 30 years. 63 retrospective longitudinal data sets in patients with TPS, ICDI or both, were collected and MRI scans reviewed. Nine patients with a clear diagnosis at presentation (two: infection, seven: histiocytosis) were excluded from subsequent analysis.

Results: Patients with TPS were older (TPS: 9.8±4.9 years) at presentation than those with ICDI (5.5±4.4 years) and TPS+ICDI (6.2±3.4 years) (P<0.04). TPS+ICDI patients were more likely (38.5%) than ICDI (5.6%) and TPS (none) to have histiocytosis. Tumours were identified in 26.9% TPS+ICDI and 27.9% ICDI, 1.0±1.4 and 1.9±2.4 years later respectively, but not in TPS. 80% TPS cases remained unexplained (vs 61.1% ICDI and 34.6% TPS+ICDI) though at a shorter follow-up (2.5 vs 5.2 and 5.8 years). Multiple anterior pituitary deficits evolved with time across groups (GHd, 45–58%, TSHd 19–30%, ACTHd 13–21%, GnRHd 7–17%) but visual deficits, present in 8–23% at presentation, increased only in TPS+ICDI (7.6 to 34.6%).

Conclusions: ICDI is a negative prognostic factor for malignant disease, whilst the combination with TPS may be a progressive phenomenon and is more often associated with histiocytosis. TPS alone is unlikely to lead to malignancy but should be prioritized for endocrine follow-up.