A cytomorphological and immunohistochemical study of bone marrow in the diagnosis of essential mixed type II cryoglobulinemia

Type II essential cryoglobulinemia may be associated with a lymphoproliferative disorder of beta lineage that shows a low degree of malignancy.The authors report a case recorded of 35 patients (30 females and 5 males) affected by mixed cryoglobulinemia type II (MC II) that has been typed by immunofixation, a procedure that allows the identification of minute amounts of monoclonal components. In 20 patients with the "essential" form, the bone marrow histology revealed the presence of nodular aggregates of lymphocytes that were consistent with the diagnosis of immunocytoma in 14 cases and of early stage plasmocytoma in 1 case. The immunohistochemical analysis carried out in 5 of these cases allowed the identification of B lymphocytes in the nodules, thus confirming the diagnosis of low malignancy lymphoma. In our series the percentage of proliferative disorders of B lymphocyte lineage was 66%.Our results indicate that the cytohistological analysis of bone marrow is highly recommended in the study of essential mixed cryoglobulinemia and that histological analysis supplemented with immunohistochemistry is preferred to the simple cytological analysis of bone aspirate.