The intracranial zone is a common site of metastasis, but metastases to the sellar and suprasellar regions are not commonly observed. An autopsy case of pituitary metastasis was reported by Benjamin for the first time in 1857. (4) Currently, the majority of cases have been identified during autopsy, while only a few cases were diagnosed via patient symptoms. The preoperative diagnosis of pituitary metastasis remains a challenge in the clinical setting. A case series and review study revealed that the main clinical symptom noted was signs of cranial hypertension. (2) In this case, the patient’s symptoms were no different from those of other sellar region diseases, but the ophthalmological examination and MRI scan revealed some intriguing results. Generally, pituitary adenoma primarily causes temporal visual field defects by oppressing the optic nerve. The atypical visual field defect may be caused by the tumor invaded the optic nerve fibrous bundle. In addition to the metastasis in the sellar region, an intracranial metastasis located in the left temporal lobe was also identified, and this tumor obtained its blood supply from the left middle cerebral artery (M1-M2). The most unique characteristic of the lesion was observed intraoperatively. It took a long time to remove the tumor tissue due to its solid consistency. Even with the use of CUSA (Cavitron ultrasonic aspiration), tumor removal remained the largest obstacle during surgery.
Subsequently, a literature review was performed by searching the PubMed database. The initial search string used was "Pituitary OR Sella OR Sellar AND Metastatic." A total of 16 patients with pituitary metastasis were reported in the previous 10 years. (5–20) The collected information and primary lesion data are presented in Table I. The average age of all patients was 61.5 years, and the number of females was twice as high as that of males (11:5). The most common primary tumor was lung carcinoma (n = 4); breast carcinoma and lymphoma were both reported twice. In addition, hepatocellular carcinoma, parotid carcinoma, colon carcinoma, prostate carcinoma, gastric carcinoma, melanoma, renal carcinoma and thyroid carcinoma were reported a single time each. In addition, there were six cases of other tissue metastases identified, including lung metastasis (n = 1), cerebral hemisphere metastasis (n = 2) and bone metastasis (n = 3).
Table II presents a symptomology graph to describe the patient presentation. The incidence of hormone secretion disorders caused by pituitary dysfunction (81.3%) was the highest, followed by intracranial hypertension (56.3%) and visual field defects (43.8%). Oculomotor nerve paralysis and reduced vision were both observed in one-third of the patients. Electrolyte imbalance, diabetes insipidus and retrobulbar pain were also reported in less than a quarter of the cases. In the majority of cases, the patient presented with pituitary dysfunction caused by anterior pituitary lobe compression and complained of listlessness, feebleness, poor appetite and weight loss. Headache, vomiting and optic disk atrophy were the main signs of intracranial hypertension, which occurred in half of these cases. These symptoms could be persistent or intermittent, with variable degrees, which was the main contributing factor for patients visiting the emergency room. Bitemporal visual field defects were a common manifestation of pituitary lesions, but in metastatic cases, the shape of the visual field defect could be atypical. There were two patients with unilateral visual field defects, while nasal visual field hemianopia was only observed in one case. Not all instances of electrolyte imbalance were caused by diabetes insipidus, but on the contrary, electrolyte imbalance did occur as a result of diabetes insipidus.
The majority of patients received MRI scans, and the image descriptions are presented in Table III. Case 12 did not include the results of the MRI scan, as the files were created in 1980, and the data were not recorded. Pituitary mass extension into the suprasellar region was revealed in eight patients (53.3%). A quarter of the cases had one or more encased intracranial arteries. A few lesions extended into the cavernous sinuses, unilaterally or bilaterally, and extended inferiorly into Meckel's cave. Two cases of pituitary apoplexy were reported, which was the main cause of severe headaches.