Stromal Composition in Bronchogenic Carcinomas - Morphometric Structure Analysis

Summary So far little is known about the pathogenesis and development of the stroma in bronchogenic neoplasia. Clinical and radiological findings and morphological pictures of the tumor taken just after resection, don't reveal information about the pathogenesis and duration of the development of the scarh tissue. Using an automatic image analyser (Quantimet 720, Imanco) it was possible to do morphometrical studies of bronchial carcinomas. We correlated the quantity of the stromal reaction in bronchial carcinomas to the size and histological type of the tumor. 60 peripheral, completely excised bronchial tumors were studied using post mortem and surgically removed specimens (25 adenocarinomas, 22 squamous cell carcinomas, 13 oat cell carcinomas). The mesenchyme was studied histologically and morphometrically at the point of largest circumference of the tumor. Different histological stains were used to identify and correlate epithelial, mesenchymal and necrotic parts of the tumor. Adenocarcinomas on average have 48% stromal composition and even tumors sized 1.5-3 cm 2 show evidence of extensive scar tissue. Squamous cell carcinomas have 37% and oat cell carcinomas have 30% fibrous tissue composition. Large adenocarcinomas have less stroma whereas large squamous cell carcinomas showed a relative increase in stromal composition. None of the above was shown in oat cell carcinomas. The amount of stromal tissue therefore depends on the histological tumor type. Squamous cell carcinomas show a more honeycomb, oat cell carcinomas a more spiderweblike structure and adenocarcinomas show a more extensive central scar tissue formation. In 30% of all tumors we found radiologically regressing changes with small calcium deposits. Analysis of non-treated carcinomas will give a basis to compare the scarring of tumors caused by therapy with scar tissue in spontaneously regressing tumors.