Endocrine Abstracts

A 31-year-old lady was referred to the outpatient endocrine clinic for subfertility, intermittent galactorrhoea and amenorrhoea since birth of her son 5 year ago. However, she denied visual disturbances and headache. She was struggling to lose weight but she had no clinical features suggestive of corticosteroid or growth hormone excess apart from an increase in her UK shoe size from 5.5 to 6.5 and family members noted her hands were slightly bigger. She was on an antidepressant, Sertraline, which was withheld for two weeks, so that a repeat pituitary profile can be carried out. It showed hypogonadotropic hypogonadism. The results were as follows: FSH 1.2 IU/l (2.5-10.2), LH <0.2 IU/l (1.9-12.5); oestradiol <55 pmol/l (55 - 422), Prolactin 1200 mIU/l (70 - 566) and IGF11 45 mol/l (10.2 to 40.7). But the Cortisol level, TSH and ACTH were within acceptable range. MRI pituitary demonstrated a pituitary/suprasellar mass with a 45mm craniocaudally dimension, which was displacing the optic chiasm superiorly and compressing on it. Formal visual field testing showed bilateral superior temporal quadrantanopia. She underwent Trans-sphenoidal surgery and was initiated on hydrocortisone replacement post-operatively. There was evidence of residual tumour in postoperative MRI scan and histology showed eosinophilic excess with intranuclear inclusions and immunohistochemistry demonstrated PIT 1 lineage pituitary adenoma, variably intense positivity for TSH predominantly, second most frequent was GH with Ki 67 3 %. Post-surgery, the Pituitary multidisciplinary team meeting (MDT), diagnosis was clinically silent and low-grade somatotroph adenoma biochemically. There was subjective improvement in the vision post operatively with normal VF confrontation and normal prolactin 289 mIU/l but persistently raised IGF153.9 mol/l. MDT noted that good debulking surgery but there was still a residual suprasellar part of tumour. Somatostatin analogue (SSA) therapy was recommended and re-do surgery for residual tumour if SSA therapy failed to achieve the therapeutic goal. The plan is to repeat MRI Pituitary and assess pituitary function with insulin tolerance test in 3 months. Learning points: This case highlights the somatotroph adenoma is presenting with a silent pituitary mass for decades and that diagnosis can be delayed until the clinical or biochemical manifestation of acromegaly. We picked up the diagnosis early by chance simply because she was investigated for subfertility. Surgical debulking surgery is main stay of treatment in somatotroph adenoma as it can lower GH levels and improve the cure rate with subsequent SSAs.