Primary extragonadal yolk sac tumor:a clinicopathologic analysis of 40 cases / 临床与实验病理学杂志

ABSTRACT

Purpose To investigate the clinicopathological features, histogenesis, morphological characteristics, immunophenotypes and differential diagnosis of primary extragonadal yolk sac tumor ( eYST) . Methods Clinicopathological data, morphological charac-teristics and immunophenotypes results of 40 cases of eYST were retrospectively studied and the relevant literatures were reviewed. Re-sults All 40 patients, which included 24 male and 16 female, aged from 6 months to 42 years with a 12 years average age and 17 (42.5%) cases were over 12 years old. Mediastinum, sacrococcygeal, retroperitoneal, pineal gland and vagina were involved in 16 (40.0%), 12(30.0%), 5(12.5%), 4(10.0%) and 3(7.5%), respectively. All 40 cases included 32(80.0%) cases pure YSTs, while other 8(20.0%) cases contained other one or two types of germ cell tumor (GCT) components. Conclusions Primary eYST is rare, mediastinum and sacrococcygeal are the most common anatomic sites for eYST, and these mediastinal tumor patients are overwhelmingly confined to adult males, whose average age are significantly older than that in sacrococcygeal, retroperitoneal, pineal gland and vaginal tumor patients (P<0.05), while other sites eYST are restricted to prepubertal children. Adult eYST contain other types of GCT components in some cases, and children's counterparts are always pure YST. Extragonadal eYST manifestate pleomorphic histological features, which combine with immunohistochemical markers is definite value for diagnosis, differential diagnosis.