Criteria for the diagnosis of Waldenstrom's macroglobulinemia (see Table 5, page 427):
(1) IgM monoclonal gammopathy of any concentration
(2) bone marrow infiltration by lymphoid cells (small lymphocytes, plasmacytoid lymphocytes, plasma cells)
(3) bone marrow infiltration shows a diffuse, interstitial or nodular pattern
(4) immunophenotypic markers (in 90%):
(4a) positive: surface immunoglobulin, CD19, CD20
(4b) negative: CD5, CD10, CD23
where:
• A paratrabecular pattern may be seen in Waldenstrom's macroglobulinemia but would be more typical for a follicular lymphoma. Biopsy of lymph node and/or PCR for t(14:18) may help diagnose the latter.
Adverse prognostic factors in multivariate analysis:
(1) age > 60 years
(2) WHO performance status >= 2 (see Chapter 1; range from mobile but unable to work to bedridden)
(3) platelet count < 100,000 per µL
Observations:
(1) The International Prognostic Index had limited use for prognosis.
(2) IgM monoclonal gammopathy may be seen in all subtypes of peripheral B-cell disorders.
