Lymphoid nodules and nodular lymphoid hyperplasia in bone marrow biopsies.

Out of 2,474 bone marrow biopsies we have observed 330 cases (13.3%) with presence of lymphoid nodules (LN). LN were frequent in old age (24.6% over 80 years), in females (17%) and in some diseases, such as rheumatoid arthritis and systemic lupus erythematosus (73.7% of the cases), partial aplasia (34%), hypersplenism (30.4%), hemopoietic dysplasia (25%), chronic renal failure (20.4%), polycythemia vera (20.2%), idiopathic thrombocytopenic purpura (18.8%), acute leukemia (17.7%). Nodular lymphoid hyperplasia of the bone marrow was found especially in systemic autoimmune diseases (26.3%), hypersplenism (9.8%), preleukemia (7.3%) and acute leukemia (4.2%). The presence of excessive medullary LN could indicate a bone marrow microenvironment damage, possibly of autoimmune origin.