Endocrine Abstracts

Pituitary apoplexy (characterised by sudden onset headache, meningism and cranial nerve defects) is an unusual but serious complication of pituitary macroadenoma. Less than 2 percent of patients with pituitary macroadenoma present initially with apoplexy. Pituitary adenoma is the presenting feature in 10–25% of cases with multiple endocrine neoplasia (MEN) type 1, with microadenomas accounting for 2/3 of MEN-related pituitary adenomas.

A 35-year-old man presented in 2003 with pituitary apoplexy (headache and visual loss). He had trans-sphenoidal decompression of a large necrotic pituitary macroadenoma and his vision improved post-operatively. He was noted to have elevated serum calcium during his post-operative recovery and was subsequently diagnosed with primary hyperparathyroidism. Genetic testing revealed a mutation in exon 4 of the MEN type 1 gene. His niece was later diagnosed with MEN following presentation with a pituitary macroadenoma and hyperparathyroidism. His brother was also diagnosed with MEN as a result of family screening.

A 54-year-old lady presented in 2006 with pituitary apoplexy (headache and visual loss). She had recently been diagnosed with primary hyperparathyroidism. She belonged to a large family and had 12 siblings, 2 sons and 36 nieces/nephews. One niece had been diagnosed with MEN type 1 in 2002 after presenting with primary hyperparathyroidism and prolactinoma. In addition, 3 of the patient’s brothers had undergone parathyroid surgery prior to 2002. Following genetic confirmation of MEN (frameshift mutation of exon 7) in the patient’s niece, family tracing and investigation had subsequently identified hyperparathyroidism in a further 3 siblings.

About 9 MEN type 1 patients with pituitary macroadenoma (4 prolactinoma; 5 non-functioning pituitary adenoma) attend our MEN clinic. The occurrence of apoplexy in patients with pituitary disease attending the clinic is most unusual. Pituitary apoplexy has not previously been reported in association with MEN. This may reflect the higher prevalence of micro compared to macroadenomas in MEN patients. Factors that predispose to apoplexy are unclear but may include differing tumour characteristics or genetic predisposition.