Progressive headache and lethargy in a middle-age female patient: question

Abstract

Following MRI and pre-operative workup, the patient underwent an endoscopic transnasal/transsphenoidal biopsy of the sella lesion with formal histopathology demonstrating malignant tumour cells which were strongly CK7 and thyroid transcription factor-1 positive and GCDFP-15, PR, HER2, CK20, CDX-2 and WT1 negative consistent with a metastasis from a lung primary cancer. The patient underwent staging CT scanning, which demonstrated a right upper lobe lung lesion associated with right hilar adenopathy and a bulky adrenal gland. The patient has commenced stereotactic radiosurgery for the pituitary metastasis and is currently on hormone replacement. Pituitary metastasis is uncommon, comprising of 0.14 to 28.1% of all brain metastases in an autopsy series [1]. The most common primary disease is breast cancer in women and lung cancer in men [2], however, it is rare that a pituitary metastasis is the first manifestation of disease [3]. Patients present with visual disturbance, particularly hemianopia, which can be explained by suprasellar extension of the tumour compressing the optic apparatus. Other cranial nerve deficits are less common but can be seen with tumour extension to the parasellar region and cavernous sinus. In a case series by McCormack et al. 70% of patients presented with diabetes insipidus. This can be attributed to posterior pituitary involvement [4]. In comparison, in the more common pituitary adenoma, diabetes insipidus is reported in only 1% of cases [5]. This also suggests the importance of the inferior hypophyseal artery as the blood supply to the posterior pituitary from the systemic circulation.