Ultrastructural morphometric study of microvilli and desmosomes of pleural malignant mesothlioma and metastatic adenocarcinoma of lung

Our observations proved that ultrastructural morphometric examination of microvilli and desmosomes may help to distinguish pleural malignant mesothelioma from metastatic adenocarcinoma of lung. In 16 cases of pleural malignant mesothliona the mean ratio of leng to width （L/W） of microvilli was 11.76, whereas in 10 cases of metastatic adenocarcinoma of lung it was 5.22. The difference between them was highly significant statistically （P＜0.001）. The lengths of desmosomes from 16 cases of malignant mesothelioma and from 10 cases of metastatic adenocarcinoma of lung were also measured. The mean length of desmosomes was not significantly different between them. However, the length of desmosomes in all cases of malignant mesothelioma was greater than 1.5um, whereas in none of 10 cases of metastatic adenocarcin oma it was more than 1.5um. The results suggest that malignant mesothelioma have longer desmosomes while matastatic adenocarcinomas have not ones of such length.