Combined epidermoid and adenocarcinoma in diffuse interstitial pulmonary fibrosis.

This report documents a case of combined epidermoid and adenocarcinoma with idiopathic diffuse interstitial fibrosis developing in the lung. This type of carcinoma with diffuse interstitial fibrosis occurs only rarely in the lungs, in contrast to such carcinoma without fibrosis, which occurs less rarely. A 79-year-old man died of respiratory insufficiency three years after the was diagnosed as having diffuse interstitial pulmonary fibrosis. Six months prior to his death. a tumor shadow was noticed on a radiograph of his chest. Postmortem examination revealed diffuse interstitial pulmonary fibrosis and a primary lung tumor situated peripherally in the right lower lobe. The histologic features of the tumor closely resembled those of mucoepidermoid carcinoma of the major bronchi. However, the tumor had no relation to any bronchi or bronchial glands, and it was evident that no relation to any bronchi or bronchial glands, and it was evident that it had originated from the surface epithelium of the abnormally altered distal airspaces of the honeycomb lung. It is suggested that the malignantly transformed cells originally possessed the potential for bidirectional differentiation to epidermoid and mucous cells.