Comparison of distinct modes of tumor cell death in Hodgkin's disease using morphology and in situ DNA fragmentation

The study examined the morphology and frequency of cell death occurring spontaneously in lymph nodes from patients with Hodgkin's disease. In addition to necrosis, which was infrequent and usually in patches, we document two cell types showing features of individual cell death: mummy cells and apoptotic cells. Mummy cells present no evidence of DNA fragmentation, but show electron microscopic features of ''dark cells.'' Apoptotic Hodgkin-Reed-Sternberg cells are found frequently and are easier to demonstrate by in situ end labeling of fragmented DNA than by light microscopy only. In many cases phagocytosis of apoptotic cells is also documented. The significance of these findings to the limited number of Hodgkin-Reed-Sternberg cells in most cases of Hodgkin's disease is discussed.