A case of Pituitary macroadenoma co-secreting TSH and GH complicated with pituitary apoplexy

Thant  Aye; Tara Kearney

doi:10.1530/endoabs.82.WA10

Background: The plurihormonal pituitary adenomas represent 10-15% of all functioning pituitary adenoma. Mixed Growth hormone and prolactin secreting adenomas are the commonest one, approximately 5% of surgically removed adenoma. Other hormonal mixture of adenoma may occur, but very rare. We present a rare case of co-secreting TSH and GH adenoma.

Clinical Case: A 45 year old gentleman, generally fit and well, presented with 3 years history of blurred vision in the right eye and generally decline in energy and low libido recently in April 2017. He was found on formal perimetry to have upper temporal visual field deficit in the right eye and visual acuity was N5 bilaterally. He denied headache and change in physical appearance. The patient was of tall stature with a Body mass index of 35.02 kg/m². There was no clinical features suggestive of acromegaly. The MRI pituitary demonstrated a 3.6 cm pituitary lesion compatible with a macroadenoma, with suprasellar extension, compressing the optic chiasma. He had biochemically evidence excess of TSH and GH level (Table¹) with nadir GH 1.27 ug/l on OGTT. Subsequently, he became thyrotoxic and commenced on carbimazole to control thyroid excess prior to definitive management alongside with testosterone replacement.

Table 1 Pituitary profile (Presentation and Post-operative)
	Initial	Post-op
TSH (0.35-5.50 mUl/l)	5.1	0.74
T4 (10-20 pmol/l)	40.1	15.1
Testosterone (8.4-28.7 nmol/l)	6.6	4
LH (2-9 U/l)	0.1	1.3
FSH (1-18U/l)	0.3	1.9
Cortisol (200-500 nmol/l)	591	504
ACTH (90-46 ng/l)	26	29.4
GH	1	0.8
IGF-1 (74-196 ng/ml)	514	436
Prolactin (45-375 mUl/l)	311	132

In July 2017, the patient had flu like symptoms with sudden onset of headache and significant visual deterioration in his right eye. An urgent MRI pituitary revealed a significant increase in tumor size with small foci of infarct, suggestive of pituitary apoplexy. Hydrocortisone was started as a precaution to address cortisol deficiency and edema due to chiasm compression. Afterwards, patient successfully had transphenoidal surgery and histology showed plurihormonal adenoma with GH and TSH excess, Ki67>10%. His visual field was significantly improved with stable anterior remnant without chiasma compromise on MRI pituitary. Post-operative pituitary profile was repeated (Table¹). Thereafter, the carbimazole was stopped. After reassurance of GST, hydrocortisone was weaned off. However, the testosterone treatment was continued for secondary hypogonadism.

Discussion: This is a rare case of TSH and GH co-secreting pituitary macroadenoma, with mass affect and hyperthyroid symptoms without clinical features of acromegaly.

Endocrine Abstracts

WA10