Role of minimal panel immunostaining in accurate diagnosis of lung cancer using small biopsies

Abstract

AbstractIntroductionIn small biopsies standard morphology cannot specifically subtype the tumor. Histologic subtyping of lung cancer is mandatory for treatment. Immunohistochemical staining is a valuable tool for diagnosis of lung cancer.AimThe aim of this study was to evaluate the diagnostic accuracy of minimal panel of Napsin A, CK 5/6 and CD 56 versus H&E of lung cancer in small biopsies.Methods84small sized tissue samples were obtained. Seventy samples were obtained via fiberoptic bronchoscope (FOB) and 14 samples were obtained with transothoracic CT guided trucut needle. All samples were stained with H&E for morphologic diagnosis, then the same samples were stained with immunohistochemical (IHC) staining including 3 antibodies (Napsin A, CK 5/6 and CD 56), then we compared the diagnostic yield of both methods.ResultsAfter H&E staining, according to WHO 2004 classification: 40 cases were adenocarcinoma (AC), 10 were squamous cell carcinoma (SCC), 22 were large cell carcinoma (LCC) and 12 were neuroendocrine tumors (NET). After IHC; 54 (64.3%) were AC, 11 (13.1%) were SCC, 11 (13.1%) were NET and 8 (9.5%) were non small cell lung cancer not otherwise specified NSCLC NOS (Counterpart of large cell carcinoma in 2004 WHO classification). Napsin A was expressed in 98% (53/54) and CK 5/6 in 90.9% (10/11) of SCC. CD 56 in 100% (11/11) of neuroendocrine tumors.ConclusionIHC with Napsin A, CK 5/6 and CD 56 has a more diagnostic value in precise typing of different cell types of lung cancer than H&E in small biopsies