(CSEMP052) GONADOTROPH ADENOMA ASSOCIATED WITH CONCURRENT MENINGIOMA

Abstract:

Background:
Pituitary tumors and meningiomas are two of the most common benign intracranial tumours, and most often associated with sex, age and previous history of irradiation. Pituitary neuroendocrine tumour (PNET) with meningioma (PNET-M) is a rare condition with the mechanism of tumorigenesis unclear. Previous studies have shown possible mechanisms, such as the upregulated mTOR signaling pathway, genetic mutations in MEN1, growth factors from PNET, However, due to the limited number of cases, the mechanisms and features of PNET-M remain unclear.

Case:
49-year-old woman who initially presented in 2018 with symptoms of fatigue, headaches and visual changes in the left eye. She had no family history of MEN. Visual field testing showed a deficit in her left eye. She subsequently had a MR sella which revealed a sellar mass with compression of the optic chiasm and right tentorial leaflet meningioma which local sinus invasion. Endocrine investigations revealed an elevated PRL of 35.6 mcg/L but were otherwise unremarkable. She underwent transsphenoidal surgery on in 2019. Pathology was consistent with a gonadotroph tumour. Post-operatively, her PRL level was normalized. She subsequently underwent an elective craniotomy for tumour resection in 2022 as although her meningioma had stayed relatively stable in size (2.6 cm x 3.4 cm x 2.7cm), it was causing some compression of the right cerebellar hemisphere and vasogenic edema. Pathology was consistent with meningioma. She was placed on dexamethasone after the surgery, which was weaned off and she has been doing well since. Her most recent MRI showed no evidence of recurrence.

Discussion:
This is an emerging area of research with preliminary studies showing there may be a common underlying germline mutation in MEN1 causing lower expression of menin and upregulation of the mTOR signalling pathway, leading to the development of PNET-M. In our patient’s case, she did not have any elevations in FSH/LH from her gonadotroph tumour but did have some hyperprolactinemia likely from stalk effect. Ciccarelli et all (J Neurosurg Sci. (2001) 45:70–4.) had reported increased prolactin receptors in meningiomas. Other studies, specifically Muccioli et all (J Endocrinol. (1997) 153:365–71) reported in-vitro growth of meningioma cell in-vitro when exposed to prolactin. Interestingly in our case, once the patient’s gonadotroph tumour had been removed, her meningioma stayed relatively stable in size.

Conclusion:
We report a rare case of PNET-M successfully treated with transsphenoidal surgery and craniotomy. More case will be required to understand the nature of this rare condition.