Relationships of morphology to clinical presentation in ten cases of early squamous cell carcinoma of the lung.

The morphologic changes in 10 patients who were found to have squamous cell carcinoma of the lung before they became evident on chest x ray are discussed. It is suggested that these cases have a long preclinical course as invasive carcinomas that ranges from a microscopic focus of microinvasion (possibly originating from in situ carcinoma in submucosal gland epithelium) to a large concentric carcinoma which may have metastasized to regional lymph nodes. Although the duration of the in situ phase of squamous cell carcinoma of the bronchus in not known, it was evident that the expanse of in situ carcinoma frequently far exceeded that of the invasive carcinoma, and usually extended proximal to the invasive lesion. It is important that the extent of the in situ lesion is determined preoperatively. Finally, multifocal in situ (or invasive) carcinoma was found in at least two of the cases, either synchronously or metachronously.