The morphology of the lymph node in the macroglobulinaemia of Waldenström.

In 16 cases of Waldenström's macroglobulinaemia the following findings were sufficiently frequent to justify a provisional diagnosis: a modestly enlarged node with lymphocytic infiltration through the capsule into the adjacent connective tissue, retention of the sinus and medullary reticulin pattern, few or no peripheral follicles, sinuses marked out by pale histiocytes, scanty mitoses, numerous plasma cells, and dark staining of plasma in blood vessels. Mast cells were not more frequent than in reactive nodes, but were more frequent than in lymphomas. Periodic acid-Schiff-positive inclusions were found in every case, but were usually very scanty. Similar inclusions can rarely be found in other cases.