Metastatic pituitary carcinoma: a case report and review of literature

Background As a kind of rare tumor, metastatic pituitary carcinoma is very difficult to diagnose clinically and is easy to be misdiagnosed. This article aims to discuss the clinical manifestations and histopathological features of this tumor. Methods The clinical presentations, histopathological features and immunophenotype were studied in one case of poorly differentiated lung adenocarcinoma metastatic to pituitary gland, and related literature was reviewed. Results A 47-year-old woman mainly presented with faint, headache and blurred vision. CT scan demonstrated abnormal signals in suprasellar cistern. During the resection, the tumor could be seen locating in sellar region, the size of which was about 2 cm × 1 cm × 1 cm. Histopathological examination revealed that the structure of pituitary gland was damaged and the tumor was composed of atypical round or oval cells arranged in nest or glandular patterns, in which a number of enlarged plump tumor cells contained abundant eosinophilic cytoplasm with eccentrical caryogenesis. The immunohistochemistry showed that epithelial membrane antigen (EMA), pan cytokeratin (PCK), thyroid transcription factor-1 (TTF-1) and cytokeratin 7 (CK7) were positive in tumor cells with Ki-67 labeling index being 15%, but chromogranin (CgA), cancer embryo antigen (CEA), human chorionic gonadotropin (hCG), placental alkaline phosphatase (PLAP), CD117, leukocyte common antigen (LCA), CD30, anaplastic lymphoma kinase-1 (ALK-1) were negative in tumor cells. After operation the patient received treatment with levothyroxine sodium and γ knife, but died 4 months later. Conclusion Histopathological examination and immunohistochemistry can confirm the diagnosis of metastatic pituitary carcinoma and locate the primary lesion. Postoperative comprehensive therapy is necessary.