Endocrine Abstracts

Background: Isolated pituitary stalk (PS) lesions/thickening detected on imaging pose challenging dilemmas.

Aim: Audit the diagnostic approach and management of patients with isolated PS lesions/thickening reported on MRI in a tertiary hospital.

Methods: Reports of pituitary/brain MRIs performed in our Radiology Department between 1/2013 and 12/2015 were searched for the terms ‘stalk’, ‘infundibular’, ‘infundibulum’. Those with abnormality not limited to the stalk and cases with previous pituitary surgery were excluded.

Results: Fifteen cases were identified (nine females, median age 48 years; range 19–91) managed by various specialists. Reasons for MRI: possible diabetes insipidus (n=3), hyperprolactinaemia (n=2), history of hypopituitarism (n=1), neurosarcoidosis (n=1), anaplastic lymphoma (n=1), spinal ependymoma (n=1), investigation of other symptoms/signs (n=6;incidental finding).

Pituitary function: FSH/LH deficient 4/15, normal 5/15, not checked 6/15; hyperprolactinaemia 4/15 (resolved in 2), normal 5/15, not checked 6/15; ACTH normal 9/15, not checked 6/15 (one on steroids); TSH deficiency 4/15, normal 10/15, not checked 1/15;diabetes insipidus 2/15. No patient had stalk biopsy. Diagnoses were hypophysitis (n=2; based on imaging findings and later reduction of lesion), neurosarcoidosis (n=2; based on previous history and biopsy of other lesions), presumed Langerhans cell histiocytosis (n=1; diagnosed 8 years later from a skin lesion-remained stable during this interval), presumed Rathke’s cleft cyst (n=1; no further follow-up deemed necessary), presumed metastasis from ependymona (n=1), progression of anaplastic lymphoma (n=1). Diagnosis was not clarified in 6 cases with stable imaging appearances (median follow-up 8 months (2–24)); their documented investigations included chest imaging n=3/6, vasculitis screen/aFP/hGC/inflammatory markers n=2/6, FDG-PET-CT n=1/6. In one case, further review was suggestive of ‘normal variation’ and had no further scans. Conclusions: Given that biopsy of isolated PS lesions/thickening is technically demanding, previous history, clinical/laboratory evaluation may narrow the diagnosis. However, in a number of cases, diagnosis is not established and investigations arranged seem to be non-comprehensive. As their natural history remains poorly understood, a robust diagnostic and management algorithm will guide all clinicians involved.