title: Immunohistochemical study of 36 cases of pulmonary sarcomatoid carcinoma--sensitivity of TTF-1 is superior to napsin.
abstract: Immunohistochemistry is often used to distinguish pulmonary sarcomatoid carcinoma from morphologic mimics. Napsin-A is a pulmonary adenocarcinoma marker, but literature on expression in sarcomatoid carcinoma is limited. Thirty-six cases of sarcomatoid carcinoma were stained for napsin, TTF-1, Oscar, CAM5.2, AE1/AE3, desmin, SMA, S-100, CK5/6, calretinin, D2-40, and WT1. Patients were 24 men and 12 women (mean, 70 years; range, 46-93). There were 27 pleomorphic carcinomas, 5 spindle cell carcinomas, 3 carcinosarcomas, and 1 giant cell carcinoma. Cases were positive for at least 1 keratin: AE1/3 was positive in all 36 cases; Oscar, in 34 cases (94%); and CAM5.2, in 32 cases (89%, weaker/more focal). Napsin was positive in 14 cases (39%): 8 diffuse, 3 focal, and 3 rare cells. TTF-1 was positive in 22 cases (61%): 15 diffuse, 3 focal, and 4 rare cells. No cases were napsin positive and negative for TTF-1. Variable staining for mesothelial markers was observed, including positivity for calretinin (12 cases, 33%), WT1 (6 cases, 17%), D2-40 (5 cases, 14%), and CK5/6 (9 cases, 25%). Mesenchymal markers were also sometimes positive (usually focal), including S-100 (4 cases, 11%), desmin (4 cases, 11%), and SMA (7 cases, 19%, 1 diffuse). In conclusion, TTF-1 is more sensitive than napsin for detection of sarcomatoid carcinoma, and no cases were positive for napsin but negative for TTF-1. CAM5.2 is less sensitive than AE1/AE3 and Oscar. Use of a thoughtful immunohistochemical panel is important in the evaluation of sarcomatoid carcinoma because mesothelial and mesenchymal markers can be expressed.
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.
authors: Simone B S P
authors: SB
authors: Terra
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.
authors: Marie Christine
authors: MC
authors: Aubry
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.
authors: Eunhee S
authors: ES
authors: Yi
authors: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA. Electronic address: boland.jennifer@mayo.edu.
authors: Jennifer M
authors: JM
authors: Boland
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016282:Aspartic Acid Endopeptidases / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000473:pathology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000473:pathology*; D002296:Carcinosarcoma / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000032:analysis*; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human
keywords: Lung sarcomatoid carcinoma; Napsin; TTF-1