Endocrine Abstracts

Case History: A female, aged eighty-three was admitted for an elective urology stent procedure. She had a background history of a non-functioning pituitary adenoma diagnosed 3 weeks before admission. This was found after investigation for headache and diplopia. The pituitary lesion was described as 18 × 17 × 14 mm in size and mixed solid/cystic in nature. There was no chiasmal compression. During that admission her case was discussed with neurosurgery and it was felt that she was not a good surgical candidate. During this elective admission for her stent she was unwell with severe headache and confusion. Pituitary function tests showed a prolactin of 900 mU/L (59-619 mU/L), TSH 0.07 mU/L, T4 17 pmol/L, IGF-1 12.7 nmol/L, LH 0.5 U/L, FSH 3.8 U/L, 9 am cortisol 570 nmol/L. An urgent CT scan was arranged to rule out pituitary apoplexy. It showed an interval increase in the size of the pituitary adenoma. We then organised a pituitary MRI scan that surprisingly showed an aggressive sella mass with surrounding invasion suggestive of pituitary metastasis. A subsequent staging scan was arranged to look for a primary that showed disseminated systemic disease with an unknown primary.

Investigation: Staging CT showed multiple lung metastasis with enlarged mediastinal and retroperitoneal nodes. There was a mass within the pancreas and associated thrombus within SMV/portal vein. There was also an abnormality within the right lobe thyroid highly suspicious of malignancy. All these findings were in keeping with metastatic disease.

Treatment: Considering the aggressive nature of the tumour with systemic metastasis and the rapid progression of metastatic lesion within pituitary, she was palliated.

Conclusion: It was debated when she re-presented whether there would be further benefit from re-scanning her given her previous medical management plan. However symptom progression led us to believe it would yield useful information. Symptomatic pituitary metastases are rare, not well documented and associated with poor prognosis. It may be difficult to differentiate adenoma from metastasis clinically and radiologically. Previous studies have reported that only 7% of pituitary metastases are symptomatic. In contrast to the adenoma, metastases are more likely to be located in the posterior pituitary in part due to the fact that this region of the gland is supplied by the systemic circulation. Literature review showed breast cancer followed by lung and thyroid cancer being the most frequent primary origin of metastases.Although rare, pituitary metastases may be the initial presentation of cancer.