title: Mediastinal and retroperitoneal teratoma with focal gastrointestinal adenocarcinoma.
abstract: We report an unusual case of gastrointestinal adenocarcinoma arising in a giant posterior mediastinal mature cystic teratoma extending into the retroperitoneum, which was treated by complete excision with a good outcome for more than 2 years. Teratomas with malignant transformation are rare non-germ cell malignant tumors arising from a preexisting mature teratoma. Histological examination revealed that the cyst wall was composed of mature ectodermal, mesodermal, and endodermal elements. Neoplastic glands with a cribriform pattern were found in a small, solid nodule. Strong cytokeratin 20 cytoplasmic immunostaining of the tumor cells supported the diagnosis of gastrointestinal adenocarcinoma. In this report, we describe the potential aggressiveness of a giant mature cystic teratoma with adenocarcinoma and suggest that complete surgical resection without adjuvant chemotherapy be considered as a therapy in the treatment of teratoma with focal malignant transformation.
authors.affiliation: Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Y-L
authors.initials: YL
authors.lastname: Chang
authors.forename: C-T
authors.initials: CT
authors.lastname: Wu
authors.forename: Y-C
authors.initials: YC
authors.lastname: Lee
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000328:Adult; D005770:Gastrointestinal Neoplasms / Q000473:pathology*; D006801:Humans; D008297:Male; D008479:Mediastinal Neoplasms / Q000473:pathology*; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D012186:Retroperitoneal Neoplasms / Q000473:pathology*; D013724:Teratoma / Q000473:pathology*