Endocrine Abstracts (2019) 65 P284 | DOI: 10.1530/endoabs.65.P284

Silent somatotroph pituitary neuroendocrine tumours (PitNETs): systematic review of cases from a Pituitary Centre

Muneer Ahmad Abdul Nazir1,2,3, Athanasios Fountas1,2,3, Kirstie Lithgow1,2,3, John Ayuk2,3, Andy Toogood2,3, Neil Gittoes1,2,3, Latha Senthil4, Han Seng Chew4, Swarupsinh Chavda4, Tim Matthews5, Ruchika Batra5, Shahzada Ahmed6, Alessandro Paluzzi7, George Tsermoulas7, Santhosh Nagaraju8, Ute Pohl8 & Niki Karavitaki1,2,3


1Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK; 2Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK; 3Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; 4Department of Radiology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; 5Department of Ophthalmology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; 6Department of Ear, Nose and Throat, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; 7Department of Neurosurgery, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; 8Department of Cellular Pathology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK


Introduction: Silent somatotroph Pituitary Neuroendocrine Tumours (PitNETs) are extremely rare (2−3% of surgically treated pituitary tumours) and data on their natural history and outcomes are scarce.

Aim: To review systematically the cases of these tumours presenting in our Centre.

Patients and methods: Patients with this diagnosis were identified from our Pituitary Registry and clinical/laboratory/imaging data were collected and analysed.

Results: Sixteen cases were identified [10 females−6 males, median age at diagnosis: 52 years (26−64)]. Two patients presented with apoplexy (13%), whereas in two, the tumour was found incidentally (13%). Visual field defects were detected in 69% of cases with available data. All tumours were macroadenomas; supra/para/infrasellar extension was present in 81%, 56% and 38%, respectively. Surgery was performed by transsphenoidal approach in 94% of cases and adjuvant radiotherapy was offered in three patients (19%) (45 Gy in 20 or 30 fractions). In all, except one case, there was partial tumour removal. During median follow-up of 12.1 years (0.25−26), seven patients had tumour regrowth (46.7% − one excluded due to short follow-up) at a median interval of 3.1 years (2.6−10.3) since surgery [50% of those treated solely by surgery (regrowth probability 55.6% at 5-years and 10-years) and 33.3% of those treated by surgery + radiotherapy]. Regrowths were managed by surgery (n=3), radiotherapy (n=1), surgery + radiotherapy (n=1) and observation (n=2). Two patients had second growth. None of the patients developed clinical acromegaly during follow-up.

Discussion/conclusions: In our series, the majority of silent somatotroph PitNETs had supra/parasellar extension. In comparison with historical data and within the constraints of our small sample size, the 10-years regrowth probability of those treated solely by surgery fall within the reported range for non-functioning PitNETs. Larger scale studies aiming to clarify whether this tumour subtype is characterised by aggressive clinical behaviour are needed.