The Journal of Thoracic and Cardiovascular Surgery, Vol 87, 274-282, Copyright © 1984 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
The biological implications of bronchial tumors
WH Warren, VA Memoli, CF Kittle, RJ Jensik, LP Faber and VE Gould
Seventy-six consecutively resected primary pulmonary tumors were assessed
first by routine light microscopy and subsequently by electron microscopy
and immunohistochemical staining techniques to precisely identify features
of differentiation. In 66% of the cases, this assessment provided
information that modified or revised the histologic diagnosis provided by
light microscopy alone. The following conclusions were reached: (1) The
term "large cell undifferentiated carcinoma" has been applied to a
heterogenous group of tumors, most of which have ultrastructural and
immunohistochemical features of differentiation not identifiable by routine
light microscopy. (2) Forty percent of the tumors previously called "large
cell undifferentiated carcinoma" have predominantly neuroendocrine
differentiation and appear to have a clinical course comparable to that of
small cell neuroendocrine carcinoma. (3) The majority of pulmonary
carcinomas (especially those previously called "poorly differentiated" or
"undifferentiated") may simultaneously demonstrate more than one pattern of
differentiation when studied by electron microscopy and
immunohistochemistry. (4) The frequency of neuroendocrine neoplasms of the
lung, as determined by these and previous studies, is considerably greater
than suspected on the basis of light microscopic studies alone. These
comprise a clinical and morphologic spectrum ranging from bronchial
carcinoid to small cell carcinoma, all of which have immunohistochemically
demonstrable hormone production, although paraneoplastic hormonal syndromes
are manifested in only a small minority of cases.
