Endocrine Abstracts

A 57-year-old man presented with a 6-month history of worsening headaches and bitemporal hemianopia on visual field examination. MRI of the brain revealed a 3 cm pituitary lesion impinging the optic chiasm and indenting the pons. Appearances of the lesion on imaging and the patient’s normal anterior pituitary hormonal profile were highly suggestive of a non-functioning pituitary adenoma and this was the presumed diagnosis. The patient underwent trans-sphenoidal resection of the tumour. Histopathology and immunohistochemical staining confirmed the unexpected diagnosis of a chordoma. Chordomas are rare malignant tumours of the axial skeleton arising from primitive remnants of the notochord. It can mimic a pituitary adenoma or craniopharyngioma. Tumours are usually slow-growing but can be locally aggressive and have high recurrence rates. Few literature reports have described pseudoprolactinomas, chordomas masquerading as prolactin-secreting tumours that may present a pre-operative diagnostic dilemma. Treatment options include extensive surgical resection, radiotherapy or both. This case demonstrates that although extremely rare, chordomas can directly involve the sellar region and mimic features of a pituitary adenoma. Clinicians should consider this as a differential diagnosis of a pituitary sellar or suprasellar mass.