CT manifestations and pathologic features of mediastinal primary small cell neuroendocrine carcinoma / 医学研究生学报

ABSTRACT

Objective Mediastinal primary small cell neuroendocrine carcinoma ( MPSCNC) is a rare neoplasm of high ma-lignant potential mostly affecting elderly and middle-aged males, which has a high rate of misdiagnosis because of its unidentified histo-genesis and lack of obvious characteristic imaging findings .This study was to investigate the CT findings and pathologic features of MP-SCNC, so as to improve the recognition and diagnostic accuracy of the disease . Methods We retrospectively analyzed the imaging and clinicopathologic data about 4 cases of pathologically confirmed MPSCNC and reviewed relevant literature . Results Of the 4 tumors, 2 were located in the anterior-middle-superior mediastinum , 1 in the anterior-superior mediastinum , and the other in the mid-dle-superior mediastinum .Three of them exhibited irregular shape , unclear boundary , and inhomogeneous density , with low-density cyst degeneration and necrosis , of which two had scattered punctate calcifications .Enhanced scanning revealed moderate uneven en-hancement in 3 cases and ring-shaped enhancement the other .Pathological findings showed small tumor cells with marked pleomor-phism, little cytoplasm, pale chromatin, inconspicuous or absent nucleoli , and obvious mitotic figures.Immunochemistry manifested positive CgA, Syn, and CK in all the 4 cases, positive NSE, CD56, and Ki-67 in 3 cases, and positive epithelial membrane antigen in 1. Conclusion A tumor located in the anterior-middle mediastinum with scattered punctate calcifications and compressing or inva-ding the adjacent mediastinal structures should be suspected as a small cell neuroendocrine carcinoma . However , definite diagnosis should be based on histopathologic and immunohistochemical exami-nations .