[Mediastinal XXXX of unknown primary site; report of a case].

@entity1 @entity5 @entity11028 @entity2580 @entity3 @entity4764 @entity420
The question whether the @entity5 is primary or metastatic sometimes arises in @entity1 with @entity5 . Especially, @entity420 presents @entity4764 in distinguishing @entity5 from secondary or deciding its origin. We reported a case of mediastinal @entity2580 . A 51-year-old female was admitted because of an abnormal shadow during mass screening. Chest X-ray showed a semicircular, well-demarcated shadow on right cardiophrenic angle. Chest computed tomography (CT) revealed a homogeneous mass, approximately 4 cm in diameter. The investigations of whole body failed to reveal any other @entity5 . At operation, the @entity5 was adherent to the esophagus but easily resected. Histologically, the @entity5 was mainly composed of signet-ring cells. Immunohistochemically, surfactant apoprotein ( @entity11028 ) was strongly demonstrated in @entity5 cells. @entity11028 is specific to the lung and the @entity5 was diagnosed as the @entity3 in mediastinal lymph nodes. The primary site was considered to exist in lung. But the primary site was not found over 46 months in spite of repeated further examinations.
