Pulmonary scar cancer. A pathologic reappraisal.

A total of 49 consecutive specimens of lung cancer were collected prospectively at surgical resection or autopsy from 40 men and nine women, aged 40-74 years. Of the 49 tumors, the gross appearance of 22 fitted the description of a scar cancer, i.e., a tumor with pleural puckering and central pigmentation. Nineteen of the "scar cancers" were peripheral (17 adenocarcinomas and two squamous cell carcinomas); three were central (one squamous cell carcinoma and two adenocarcinomas). In the 19 peripheral "scar cancers," elastic stains demonstrated the presence of collapsed, unfibrosed lung tissue at the center with traction of the overlying pleura toward it. Elsewhere in the tumor, the elastic framework was either destroyed or expanded by tumor filling the alveolar spaces. None of the "scar cancers" had a significant desmoplastic reaction that might otherwise explain the scarred appearance. It appeared that local atelectasis was solely responsible for the pleural puckering and central pigmentation. On the other hand, atelectatic lung tissue was not seen in the 27 cancers that did not have the appearance of a scar cancer. Tuberculosis was found in 10 of the 49 lung specimens. In only one specimen was the tuberculous lesion anatomically associated with the tumor. There was no evidence of pulmonary infarct in any of the specimens. The term "scar cancer" was considered inappropriate as there was no preformed fibrous tissue. The scarred appearance was thought to be the result of localized pulmonary atelectasis owing to small airways obstruction by tumor. Association with tuberculosis was considered incidental.