The lacunar cells and its relationship to interdigitating reticulum cells

Lacunar cells, which are characteristic of the nodular sclerosis type of Hodgkin's disease, were investigated by light and electron microscopy and by enzyme cytochemical and immunohistochemical methods. Characteristic ultrastructural features of the lacunar cells were its size, its multilobated nucleus, and the pale cytoplasm containing only a few organelles. These features distinguish the lacunar cell from typical Sternberg-Reed and Hodgkin cells. Enzyme cytochemically, lacunar cells were weakly positive for acid phosphatase and non-specific esterase. the reaction product was distributed either diffusely or more focally in the cytoplasm. By immunostaining, kappa, lambda, and IgG could be detected in some lacunar cells. The immunostaining pattern was bitypic, which might have resulted from non-specific uptake. All the results of the present study indicate that lacunar cells are non-lymphoid cells. When lacunar cells were compared with cells of normal lymphoid tissue, their ultrastructure was found to be very similar to that of interdigitating reticulum cells. Both cell types showed a bizzarrely shaped nucleus and an electron-transparent cytoplasm with only some vesicles and tubules. Furthermore, lacunar cells and interdigitating reticulum cells exhibited a similar reaction pattern of acid phosphatase and non-specific esterase. Thus, from a cytologic and enzyme cytochemical point of view, a direct relationship between the two cell types is very likely.