Several disease processes may result in panhypopituitarism and infundibulo-hypophyseal enlargement. We present a case of a 27 year old man who presented with a three month history of intermittent headaches, diplopia, lethargy, polyuria, polydipsia and low libido. Biochemical testing revealed hypopituitarism and diabetes insipidus. Magnetic resonance imaging was reported as being consistent with infundibulohypophysitis as well as a benign pineocytoma. Syphilis serology was positive, serum IgG4 and serum angiotensin-converting enzyme were elevated, and B-hCG and alpha-foeto-protein were normal. The patient improved clinically with hormone replacement therapy alone but represented three weeks later with worsening headaches, diplopia and impaired conjugate upward gaze consistent with Parinaud’s syndrome. Progress imaging revealed a significant increase in size of the pineal lesion and new leptomeningeal involvement. The patient subsequently underwent urgent transphenoidal pituitary biopsy with histology consistent with a germ cell tumour. This case highlights the difficulties faced by clinicians when trying to establish a diagnosis in patients presenting with disease of the infundibulum and hypophysis. It also places emphasis on the importance of ongoing monitoring for clinical changes in these patients.