title: Primary thymic mucinous adenocarcinoma: a case report.
abstract: Primary thymic mucinous adenocarcinoma is an extremely rare aggressive subtype of thymic carcinoma. With a review of literatures, only nine cases have been reported up to present. A 36-year-old woman was admitted for further evaluation and treatment of a mediastinal mass. The patient had no medical history of cancer. The clinicoradiological examination disclosed no tumor elsewhere. After the surgical excision of mediastinal mass, it was grossly a round semi-solid mass with mucin-filled cystic areas. Microscopically solid areas showed cords, small nests and dilated glands infiltrating the fibrotic parenchyma, while the cystic areas were lined by mucinous epithelium with tumor cells floating in extracellular-mucin pools. Some cystic walls underwent malignant transformation of the benign thymic epithelium. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) 7, CK20, CD5, and CDX-2, and negative for thyroid transcription factor-1. In conclusion, the mucinous thymic adenocarcinoma should be recognized as a separate histopathological entity and considered in the differential diagnosis of mediastinal carcinomas.
authors.affiliation: Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Korea.
authors.forename: Jamshid
authors.initials: J
authors.lastname: Abdul-Ghafar
authors.forename: Suk-Joong
authors.initials: SJ
authors.lastname: Yong
authors.forename: Woocheol
authors.initials: W
authors.lastname: Kwon
authors.forename: Il Hwan
authors.initials: IH
authors.lastname: Park
authors.forename: Soon-Hee
authors.initials: SH
authors.lastname: Jung
keywords: Adenocarcinoma, mucinous; Immunohistochemistry; Mediastinal cyst; Thymus gland