Giant cell formation in small cell carcinoma of the lung.

Four patients with biopsy proven small cell carcinoma of the lung died rapidly following radiotherapy. At autopsy areas of prominent tumor giant cell formation were found at the primary site in all four and in the metastatic sites in three. Giant cell formation in a tumor may be from the development of another tumor, sublethal damage to the original tumor cells or presence of the two components from the outset. The light and electron microscopic appearances of the giant tumor cells and their existence in the nonradiated sites in our cases suggest that small cell carcinoma, as adenocarcinomas and squamous cell carcinomas, may be associated with giant cell carcinoma-like components.