Four cases of primary @entity2970 of the anterior @entity6830 are described. The @entity1 were all @entity1 between the ages of 26 and 40 years (median 33). Clinically, they all presented with a history of @entity662 of several weeks' duration. None of the @entity1 had a history of germ cell @entity5 elsewhere or evidence of any @entity409 . Grossly, all the @entity5 were described as large mediastinal masses that impinged on adjacent structures. Histologically, they were characterized by sheets of medium-sized, round to polygonal neoplastic cells with moderate amounts of eosinophilic cytoplasm and round to oval nuclei with prominent nucleoli. The cellular proliferation was homogeneous and displayed moderate @entity465 and scattered mitotic activity. All the @entity5 showed focally the presence of more conventional areas of yolk sac @entity5 , with islands of @entity5 cells showing a reticular pattern of growth admixed with scattered intra- and extracellular hyaline globules and occasional Schiller-Duval bodies. Immunohistochemical studies showed strong positivity of the @entity5 cells for @entity160 in both components of the lesions. Follow-up information was available in three @entity1 , all of whom developed lung metastases within a year after initial diagnosis. Two of these @entity1 died of @entity5 within the same period, whereas a third @entity1 has been lost to follow-up. The present cases illustrate an unusual histologic pattern of yolk sac @entity5 in the @entity6830 and highlight the importance of considering this @entity5 in the differential diagnosis of lesions showing a hepatoid pattern of growth in the mediastinal area.

XXXX of the @entity6830 : a clinicopathologic and immunohistochemical study of four cases.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient', 'men'] @entity662 :: ('MESH:D002637', 'Disease') :: ['shortness of breath and chest pain'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'tumors'] @entity2970 :: ('MESH:D018240', 'Disease') :: ['hepatoid yolk sac tumors'] @entity409 :: ('MESH:D008107', 'Disease') :: ['hepatic abnormality'] @entity465 :: ('MESH:D007153', 'Disease') :: ['cellular atypia'] @entity160 :: ('174', 'Gene') :: ['alpha-fetoprotein'] @entity6830 :: ('MESH:D008479', 'Disease') :: ['mediastinum']
@entity2970 :: (MESH:D018240,Disease) :: ['Hepatoid yolk sac tumors']
