@entity189 or a @entity189 component has been reported in the ovary, breast, and urinary bladder and is generally thought to have prognostic significance. However, little has been written on micropapillary differentiation in @entity2 . We studied 35 cases of primary @entity2220 with a micropapillary component seen at the M.D. Anderson @entity5 Center. The micropapillary component in these @entity5 ranged from focal to prominent and was seen at both primary and metastatic sites. This component was not associated with any particular histologic @entity2220 . Of the 15 cases with available material, 14 (93%) stained positive for @entity5822 , whereas only two of the 15 cases (13%) stained positive for @entity2225 . @entity7457 immunostaining of @entity5 nuclei was seen in 12 of the 15 cases (80%). Immunostaining was seen in areas both with and without micropapillary differentiation. Thirty-three of 35 @entity1 (94%) developed @entity3 , which occurred most commonly in the lymph nodes (n = 26), and also in the lung (n = 17), brain (n = 9 cases), bone (n = 9 cases), and other sites. Most @entity3 had a prominent micropapillary component, irrespective of the extent of the @entity189 component in the primary @entity2 . Adequate clinical follow-up information was available for 29 @entity1 . The mean follow-up was 25 months. At their last follow-up, 16 of 29 @entity1 (55%) were still alive with disease, 5 (17%) were @entity66 , and 8 (28%) were alive with no evidence of disease. We believe that a micropapillary component occurring in @entity2220 should be reported, as this component may be more likely to @entity3 . The presence of this component should alert the clinician to search more carefully for @entity3 and have a closer follow-up on these @entity1 . It is also important to recognize this component in evaluating a @entity3 from an unknown primary site, as it should alert the pathologist to a possible primary in the lung in addition to breast, urinary bladder, and ovary.

XXXX : a distinctive histologic feature with possible prognostic significance.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity66 :: ('MESH:D004194', 'Disease') :: ['dead of disease'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'tumors', 'Cancer'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung tumor', 'lung carcinoma'] @entity2225 :: ('54474', 'Gene') :: ['cytokeratin 20'] @entity189 :: ('MESH:D002277', 'Disease') :: ['micropapillary carcinoma', 'Micropapillary carcinoma'] @entity5822 :: ('3855', 'Gene') :: ['cytokeratin 7'] @entity3 :: ('MESH:D009362', 'Disease') :: ['metastasis', 'metastases', 'metastasize'] @entity2220 :: ('MESH:C538231', 'Disease') :: ['lung adenocarcinoma', 'subtype of lung adenocarcinoma'] @entity7457 :: ('7080', 'Gene') :: ['Thyroid transcription factor-1']
@entity2220 :: (MESH:C538231,Disease) :: ['Micropapillary component in lung adenocarcinoma']
