Endocrine Abstracts

Introduction: Pituitary metastases account for approximately 1% of pituitary lesions, most frequently originating from lung or breast cancer. We describe a case of a pituitary metastasis from colon cancer, a rare origin.

Case report: a 36 year-old male, previously healthy, came to the emergency department for new onset jaundice and fever. He also had headaches for the last 3 months, and for the last month diplopia, left palpebral ptosis and low libido. Physical examination confirmed jaundice (sclera and skin), low weight, abdominal pain at the right upper quadrant, left palpebral ptosis and right III and VI nerve paralysis. Abdominal-pelvic CT revealed hepatomegaly with several lesions (suggesting metastases), multiple mesenteral, lombo-aortic, pelvic and inguinal adenopathies and an infiltrative mass in the sigmoid colon. The remaining investigation confirmed the diagnosis of metastatic colon cancer with obstructive jaundice and cholangitis. Brain MRI showed an extensive, infiltrative sellar and clival mass, with suprasellar extension causing optic chiasm and hypothalamic compression, bilateral cavernous sinus invasion (knosp 4), sphenoid sinus invasion and bone erosion and extension to petrous bone apex with left Meckel cavum obliteration, suggestive of metastasis in this clinical picture. 18F-FDG PET-CT revealed high uptake by the sellar lesion (as well as for the primary tumor and remaining metastases). Pituitary function tests revealed pan-hypopituitarism and slight prolactin elevation. He was started on hydrocortisone and levothyroxine. A few days later, the patient complained of increased thirst and urinary output (polyuria confirmed by 24h urine collection), with dehydration at physical examination. Diabetes insipidus was confirmed, so desmopressin was started. The patient started complaining of decreased sensation in the left upper face and it was decided to do palliative radiation treatment (30Gy), that was ineffective for symptom control and he died shortly after the end of treatment, with progressing systemic disease. Overall, the patient survived for 2 months after diagnosis and never started systemic treatment for his cancer nor transsphenoidal surgery was considered because his physical condition never allowed to.

Conclusion: Although it was not confirmed histologically, aggressive characteristics in MRI, 18F-FDG uptake, diabetes insipidus and a confirmed metastatic colon cancer diagnosis, makes pituitary metastasis the most likely diagnosis. There are only a few cases of pituitary metastases from colon cancer described in literature, usually presenting with visual complaints, most of them treated surgically, with poor prognosis.