Colon Cancer Presenting as Pituitary Mass and Hypopituitarism: Recognition and Multidisciplinary Approach of a Rare Case.

Pituitary metastases are rare. Until now, few cases have been reported; about 50% of pituitary metastases originate from breast or lung cancers. We describe the clinical case of a primary colon carcinoma first presenting with a pituitary metastasis. A 76-year-old woman, with no history of malignancy, presented with headache, dizziness, and diplopia, at the Emergency Department. The neurologic examination was remarkable for complete left ophthalmoplegia with sensitivity deficit on the left side of the face. Radiologic investigations documented a voluminous sellar and suprasellar lesion, with extension in the left cavernous sinus and temporal lobe. Pituitary hormone levels were suggestive of anterior hypopituitarism and mild hyperprolactinemia. Subtotal surgical removal of the lesion was achieved through a trans-sphenoidal endoscopic endonasal approach. The histological examination disclosed a metastasis of gastrointestinal adenocarcinoma. A subsequent colonoscopy identified right colon cancer. A contrasted total-body computerized tomography ruled out other metastases. Postsurgical MRI showed a stable parasellar residual tumor. Conventional radiotherapy was scheduled. This case underlines the importance of considering pituitary metastases in the differential diagnosis of aggressive pituitary lesions, which should be managed in a pituitary tumor center of excellence through a multidisciplinary approach, for the complexity in diagnosis and therapeutic management of this rare condition.