Atypical lung carcinoid metastasis to the pituitary gland

Abstract

Objective To study clinicopathological features, diagnosis and differential diagnosis of atypical lung carcinoid metastasis to the pituitary gland based on clinical data of one patient.  Methods and Results A 81-year-old female presented headache and sudden blindness, and head MRI showed that there was a lesion at the saddle area. The tumor was detected at intrasellar and in grayish red during surgery. The diameter of tumor was 2 cm. The tumor was soft with no envelop at and well-defined margins, and insufficiency in blood supply. The tumor was removed completely along its edge. Under optical microscopy, the tumor was consisted of small round cells of the same size. Tumor cells were distributed around blood vessels in a nest manner or diffuse manner with brisk mitotic activity and focal necrosis. By using immunohistochemical staining, the tumor cells were diffusely positive for synaptophysin (Syn), CD56 and thyoid transcription factor - 1 (TTF - 1), focal positive for cytokeratin (CK) and P53, and negative for growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), S-100 protein (S-100), thyroglobulin (TG) and calcitonin. Ki?67 labeling index was about 33%. Conclusions Pituitary metastasis is a rare tumor, and only a few cases of atypical lung carcinoid metastasis to the pituitary gland have been reported. Definite diagnosis could be made by history, typical histopathological characteristics and immunohistochemical expressions. DOI: 10.3969/j.issn.1672-6731.2017.09.010