[Clinicopathologic features of lymphoplasmacytic lymphoma]

To explore the clinicopathologic features of lymphoplasmacytic lymphomas (LPL).

Routine histological examination was performed on hematoxylin-eosin stained sections of 24 bone marrow biopsies and available 6 concurrent lymph node specimens. Immunohistochemistry study was performed using EliVision methods.

Among 24 cases, the male-to-female ratio was 2.4:1 and the median age was 59.5 years (42 - 75). The most common symptom was weakness (83.3%, 20/24). Hyperviscosity and "B" symptoms occurred in 20.8% (5/24) and 8.3% (2/24) respectively. 41.7% (10/24) patients presented with lymphadenopathy. Anemia, leukocytosis and thrombocytopenia were seen in 79.2% (19/24), 8.3% (2/24) and 37.5% (9/24) respectively. Monoclonal Ig light chain expression was detected by serum immunofixation electrophoresis in 23 cases (95.8%), including IgM (20 cases), IgG (2 cases) and IgA (1 case). Basing on the histology and immunohistochemistry findings, the diagnosis was made in 22 bone marrow and 2 lymph node biopsies, respectively. Histologically, the bone marrow and lymph node specimens composed of small lymphocytes, plasmacytoid lymphocytes and plasma cells. The most frequent pattern of bone marrow involvement was diffuse in appearance (63.6%, 14/22), while nodular and interstitial patterns were less common (22.7%, 5/22 and 13.6%, 3/22, respectively). Lymph node involvement was also to be diffuse in pattern. The proliferative cells expressed Pax5, CD20, CD38 and CD138, but were negative for CD5, CD10, CD23, CyclinD1, CD3, CD7 and MPO.

LPL has distinct clinicopathological features. Histological and immunohistochemistry findings are important for its differential diagnosis with chronic lymphocytic leukemia/small lymphocytic lymphoma, splenic marginal zone lymphoma and follicular lymphoma. Waldenström macroglobulinemia is LPL.