Pituitary gland metastasis from rectal cancer: report of a case and literature review

Abstract

Pituitary metastases are unusual complications of malignancies. In about only 2% of patients they origin from colorectal cancer (CRC), with breast and lung as the most common primary tumors. Nevertheless, some authors reported a recent increase of the incidence of metastases in infrequent sites, such as brain or bone, arising from gastrointestinal cancers, probably due to the expanded treatment options and the resulting improved survival. Here, we report the case of a 54-year old woman diagnosed with lung metastases from rectal cancer, who, after several cycles of radio- and chemotherapy, presented symptoms and signs of pituitary disfunction (i.e. diabetes insipidus, hypothyroidism and diplopy). The diagnosis of pituitary metastasis from rectal cancer was histologically confirmed after surgery.

Pituitary Incidentaloma Found on O-(2-18F-Fluoroethyl)-L-Tyrosine PET

“…Pituitary metastases, first described in 1857 (15), are a rare complication generally associated with advanced disease in cancer patients (15,17,18). The literature is mixed; however, on the basis of autopsy, it is generally reported that 1%-3.6% of cancer patients have pituitary metastases (17,19,20).…”

“…The literature is mixed; however, on the basis of autopsy, it is generally reported that 1%-3.6% of cancer patients have pituitary metastases (17,19,20). Pituitary metastases represent only 1% of all pituitary lesions, but the percentage of all brain metastases represented by pituitary metastases has been reported to be as high as 28% (15,18).…”

“…Pituitary metastases represent only 1% of all pituitary lesions, but the percentage of all brain metastases represented by pituitary metastases has been reported to be as high as 28% (15,18). In women, breast cancer is the most common tumor to metastasize to the pituitary, and for men it is lung cancer (15,17,20,21), with 20%-30% of pituitary metastases linked to breast cancer and 30%-50% to lung cancer (18). A large series of 380 cases showed that 40% of metastatic pituitary disease arose from breast cancer and 24% from lung cancer (15).…”

“…For breast cancer, it is thought that the hormonerich pituitary gland offers favorable conditions for metastatic disease (enhanced proliferation), resulting in pituitary metastases in as many as 29% of breast cancer patients (15,(22)(23)(24)(25)(26). Pituitary metastases are more common in the posterior lobe than in the anterior lobe (85% vs. 15%) (15,17), because there is direct hematogenous spread to the posterior lobe via hypophyseal arteries whereas the anterior lobe is supplied via a portal supply (no arterial supply) (15). Pituitary metastasis has several recognized pathways, including direct hematogenous spread (posterior lobe), secondary spread via portal vessels from metastases in other structures, extension of local metastases in the skull base, spread through the meninges, and contiguous spread (from posterior to anterior lobes) (15).…”

“…Antemortem differentiation of pituitary adenoma from metastases is difficult (15,17). CT and MR imaging are generally not specific (15,18,28), and a definitive diagnosis based on histologic evaluation (29) may be undesirable.…”