The site of lymphatic blockade in endemic (non-filarial) elephantiasis of the lower legs.

1. The femoral lymph nodes of 13 patients with endemic (non-filarial) elephantiasis of the lower legs are compared with those of 13 non-elephantiasic adults from the same area. 2. Features characteristic of the disease include reflux of darkly-staining lymphocytes into the afferent lymphatics, crowding of the small lymphocytes into the sinuses with sheets of similar cells in the periphery of the node. The phenomena occur in relation with endolymphangitis of afferent lymphatics in some cases. 3. The picture closely resembles that produced experimentally in animals by occlusion of the incoming lymphatics and is interpreted as indicating delay in, or absence of, transport of the lymphocytes through the node into the central circulation (Gowans cycle). In elephantiasis, the loss of lymph-flow results from endolymphangitis of the afferent lymphatics. 4. The presence of microgranulomata and of birefringent particles was also noted but is not discussed here. 5. The present study indicates that the lesion responsible for the irreversible elephantiasis of the lower legs is in the distal lymphatics.