Endocrine Abstracts

Background: Pituitary metastasis, although rare, is life-threatening often presenting with visual disturbances, hypopituitarism and AVP deficiency. The most common primary sites are breast and lung carcinomas. We highlight such a case of non-small cell lung cancer (NSCLC) presenting with pituitary metastasis.

Case Presentation: A 52-year-old, ex-smoker, presented with headaches, visual disturbances and profound fatigue. Biochemistry confirmed hypopituitarism: Na 144mmol/l, LH <0.5iu/l, FSH <0.5iu/l, Testosterone <0.3nmol/l Cortisol 99nmol/l, IGF1 143ng/mL, Growth hormone 0.9 mg/l, TSH 0.06mIU/l, fT4 7.4pmol/l, Prolactin 74mIU/l. Pituitary MRI demonstrated a 17mm heterogeneous intra and suprasellar mass, compressing the optic chiasm and consistent with a pituitary macroadenoma. Hormone replacement with hydrocortisone, thyroxine and testosterone was initiated. Within two weeks, he re-presented with worsening headaches, confusion, polydipsia and polyuria and was subsequently started on desmopressin. Repeat MRI revealed rapid interval growth, raising suspicion of an infiltrative pathology. CT CAP identified a 5 cm lung mass, histologically confirmed as NSCLC. Following pituitary and lung MDT discussions, the pros and cons of debulking surgery were discussed with the patient and his partner. They opted for surgery despite significant risks, with the hope of post-operative chemotherapy. Craniotomy with EVD, followed by a second surgery was needed for maximal tumour resection. Post operatively, he remained confused with difficult sodium/AVP-D management. A ‘smart catheter’ was used to assist with fluid balance. Unfortunately, he did not tolerate chemotherapy, and palliative care supported his terminal period. His partner was thankful for the extra time surgery provided, as he would have died much sooner without surgery.

Conclusion: This case illustrates the aggressive progression of NSCLC-related pituitary metastasis, challenges in surgical decision-making, AVP-D management, and palliative care in panhypopituitarism. Rapid-onset symptoms with a heterogeneous pituitary mass on MRI warrant urgent follow-up MRI and CT CAP. Any pituitary mass presenting with AVP-D should prompt consideration of metastatic malignancy.