ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2017) 51 OC5.1 | DOI: 10.1530/endoabs.51.OC5.1

New insights into the preoperative localisation of corticotroph adenomas in paediatric Cushing's disease (CD)

Ingrid C.E. Wilkinson1, Jane Evanson2, Matthew Matson2, Katherine Miszkiel3, Joan Grieve4, Ian Sabin5, Farhad Afshar5, Lee Martin6, Ashley B. Grossman7, Scott Akker1, Martin O. Savage1, William M. Drake1 & Helen L. Storr1

1William Harvey Research Institute, Centre for Endocrinology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, First Floor, John Vane Science Centre, Charterhouse Square, London, UK; 2Departments of Radiology, St Bartholomew’s Hospital, West Smithfield, London, UK; 3The Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; 4Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; 5Departments of Neurosurgery, St Bartholomew’s Hospital, West Smithfield, London, UK; 6Department of Paediatric Endocrinology, Royal London Hospital, Whitechapel Road, Whitechapel, London, UK; 7Department of Endocrinology, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK.

Introduction: Selective transsphenoidal microadenomectomy (TSS) is the first-line treatment of paediatric Cushing’s disease (CD). Corticotroph adenomas in children are often small and difficult to visualize. We aimed to assess the utility of pituitary MRI and bilateral inferior petrosal sinus sampling (BIPSS) in confirming the diagnosis of CD and the localisation of the adenoma. We also report our early experience of STEALTH MRI (volumetric T1 weighted, contrast-enhanced scan).

Methods: Fifty one paediatric CD patients have been managed by our centre since 1982. In 40 children (21 M) mean age 12.9 years (5.6–17.8), we had data for BIPSS, pituitary MRI and TSS findings (nine did not have BIPSS, two had surgery elsewhere). An inferior petrosal sinus to peripheral (IPS/P) plasma ACTH ratio before CRH >2.0, or peak IPS/P ratio after CRH >3.0 were considered diagnostic for central ACTH secretion. An inter-petrosal sinus gradient (IPSG) after CRH of >1.4 was considered positive for ACTH lateralisation. 39 had pituitary MRI and one patient had a CT scan. Four patients (4F, aged 11.2–16.0 year) had pre-operative STEALTH MRI recently introduced for surgical planning.

Results: BIPSS correctly identified central ACTH production in 37/40 (93%) and the adenoma position in 27/40 (68%) cases. Conventional MRI scanning identified a pituitary lesion in 18/40 (45%) cases and there was concordance of the position of the adenoma with operative findings during TSS in only 15/40 (38%) children. Following TSS, 31/40 (78%) children were in remission (0900 serum cortisol <50 nmol/l). BIPSS and MRI demonstrated the correct adenoma position in 22/31 (71%) and 10/31 (32%) remission patients, respectively. four patients had additional STEALTH MRI scans (3/4 had inconclusive conventional MRI/BIPSS findings). In all four patients, STEALTH MRI correctly identified the position of the adenoma and all are in post-operative remission.

Discussion: BIPSS is safe and well tolerated in children when performed by an experienced radiologist. BIPSS achieves a high diagnosis rate of central ACTH production in paediatric CD although evidence of adenoma position is less accurate. Microadenoma visualisation rate with conventional MRI scanning is low, however stealth MRI may emerge as a new improved technique for pituitary imaging in paediatric CD.