Neuroendocrine differentiation in poorly differentiated lung carcinomas: a light microscopic and immunohistologic study.
Frozen, unfixed tissue sections from 56 poorly differentiated, non-small cell primary lung tumors were examined by the immunoperoxidase technique with a panel of monoclonal antibodies to neuroendocrine (chromogranin A (CGA), synaptophysin (SYN), S-100) and intermediate filament (cytokeratin, vimentin, neurofilament) antigens. Although light microscopic features of neuroendocrine (NE) differentiation were not present, staining for CGA and/or SYN was identified in 5/17 (29%) large cell carcinomas (LCC) and 4/19 (21%) poorly differentiated adenocarcinomas (PDA). Diffuse, strong SYN staining was present in two LCC and one PDA. Heterogeneous intermediate filament expression (vimentin and/or neurofilament) was frequent (LCC, 10/17 (59%); PDA, 10/19 (53%)) and accompanied NE markers in 8/9 (89%) cases. Poorly differentiated squamous carcinomas were more homogeneous, with focal SYN in only 1/20 (5%) and focal presence of intermediate filaments other than cytokeratin in only 2/20 (10%). We conclude: (a) immunohistologic evidence of NE differentiation is present in a significant proportion of pulmonary large cell and poorly differentiated adenocarcinomas and rare in poorly differentiated squamous carcinomas; (b) NE differentiation is generally accompanied by heterogeneous intermediate filament expression; (c) divergent NE differentiation is not necessarily reflected by light microscopic features.
Visscher
D W
DW
Department of Pathology, Henry Ford Hospital, Detroit, Michigan.
Zarbo
R J
RJ
Trojanowski
J Q
JQ
Sakr
W
W
Crissman
J D
JD
D000230:Adenocarcinoma / Q000737:chemistry / Q000473:pathology; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000473:pathology; D002454:Cell Differentiation; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000737:chemistry / Q000473:pathology*; D009490:Neurosecretory Systems / Q000737:chemistry / Q000473:pathology*