[Clinico-pathological analysis of interstitial pneumonia associated with collagen vascular disease in patients with lung cancer].

We investigated interstitial pneumonia associated with collagen vascular disease (IP-CVD) in association with lung cancer. Seventy-three cases of IP-CVD were included in this study. Nine (12%) of the 73 cases were associated with lung cancer, one of which had double lung cancers. The histological types of the cancers were adenocarcinoma (5 cases), epidermoid carcinoma (2 cases), small cell carcinoma, large cell carcinoma and large cell neuroendocrine carcinoma (one case each). The lesions were located in the central or peripheral lung in 3 and 7 of the ten cancers, respectively. Of the seven cases diagnosed as having IP-CVD followed by lung cancer, five had stage I disease, and one each of the remaining two cases was in stage IIIA and stage IV. Six of the seven peripheral cancer lesions which were resected or autopsied could be analyzed with regard to the topographical relationship between the primary site and fibrotic lesions. Only three cancers were encased by or in close proximity to, honeycomb lung, although most of the lung cancers arose in relation to fibrotic lesions. Moreover, the acute exacerbation of IP-CVD after operation or chemotherapy without thoracic irradiation should be monitored carefully.