Case 8: Diagnostic Case

A 65-year-old man presented with acute polyuria and polydipsia. A formal water deprivation test confirmed central diabetes insipidus. Anterior pituitary assessment showed hypogonadotrophic hypogonadism and complete growth hormone deficiency with normal prolactin, free thyroxine, and cortisol. Brain magnetic resonance imaging (MRI) revealed markedly thickened and enhancing pituitary stalk with loss of inferior tapering, associated with left-sided pituitary enlargement without basilar meningeal enhancement. Follow up MRI 1 year later showed a new 11 mm, T2 isointense, enhancing left retro-orbital nodule and a polypoid lesion in the left anterosuperior aspect of the nasal cavity. Because the lesion was non-expanding, pituitary and retro-orbital biopsies were deferred. Trans-nasal biopsy of the nasal cavity lesion showed only respiratory mucosa with inflammatory infiltrate. The patient was treated with testosterone, growth hormone, and desmopressin replacement with good clinical effect.

Questions

What are the major findings and H&E diagnosis?

What are the differential diagnoses? What tests are recommended?

What is the expected impact on other central nervous system structures?

Materials submitted:

Pending.