Leukemic Involvement Is a Common Feature in Waldenström Macroglobulinemia at Diagnosis

Waldenström Macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with bone marrow (BM) involvement and IgM monoclonal gammopathy. To date, no studies have focused specifically on peripheral blood (PB) involvement. In this study, 100 patients diagnosed with WM according to the World Health Organization (WHO) criteria were included based on the demonstration of MYD88mut in BM and the availability of PB multiparametric flow cytometry (MFC) analysis. Leukemic involvement by MFC was detected in 50/100 patients. A low percentage of mature small lymphocytes in PB smears was observed in only 15 cases. MYD88mut by AS-qPCR was detected in PB in 65/100 cases. In cases with leukemic expression by MFC, MYD88mut was detected in all cases, and IGH was rearranged in 44/49 cases. In 21/50 patients without PB involvement by MFC, molecular data were consistent with circulating disease (MYD88mut by AS-qPCR 3/50, IGH rearranged 6/50, both 12/50). Therefore, PB involvement by standard techniques was detected in 71/100 patients. MYD88mut was detected in PB by dPCR in 9/29 triple negative cases. Overall, 80% of the patients presented PB involvement by any technique. Our findings support the role of PB MFC in the evaluation of patients with IgM monoclonal gammopathy and provide reliable information on correlation with molecular features. The development of a feasible MFC assay may stand as an objective tool in the classification of mature B cell neoplasms presenting with IgM monoclonal gammopathy.

Peripheral blood involvement in angioimmunoblastic T-cell lymphoma: a case report and review of the literature

Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive variant of peripheral T-cell lymphoma, occurring in elderly patients without any gender predisposition. It accounts for 1-2% of all non-Hodgkin lymphoma. Although characterized by some peculiar histological features, diagnosis of AITL can sometimes be challenging and a definite diagnosis requires a complete immunophenotypic and molecular workup. Peripheral Blood (PB) involvement in AITL has not been studied in detail and there is a paucity of published data about leukemic presentation of AITL. We present a case of a 38-year-old female diagnosed as AITL with PB involvement. Flow cytometric (FCM) examination of PB showed 40% abnormal lymphoid cells which were CD45+, CD4+, CD2+, cCD3+, CD5+, CD10+, CD16+ and TCRγδ restricted. PB involvement by AITL appears to be more common and under-reported. Nevertheless, detection of these tumoral T lymphocytes needs to be assessed in large case studies for assessing the true incidence of PB involvement. FCM analysis is an effective and reliable approach in the identification of leukemic phase of AITL and can lead to timely and effective intervention.

Peripheral blood involvement in patients with follicular lymphoma: a rare disease manifestation associated with poor prognosis

Follicular Lymphoma (FL) is the second most common non-Hodgkin lymphoma (NHL) subtype and its course is heterogeneous. At diagnosis, some patients with FL manifest a detectable leukaemic phase (FL-LP), but this feature has been seldom described and is poorly characterized. Among 499 patients diagnosed with FL in Lyon-Sud hospital, 37 (7·4%) had characteristic FL-LP (by cytological blood smears and flow cytometric analysis). In addition, 91/1135 FL patients from the PRIMA study presented FL-LP at study entry. In order to evaluate the outcome of this Lyon-Sud cohort, FL-LP patients were matched with 111 newly diagnosed FL without LP according to the Follicular Lymphoma International Prognostic Index (FLIPI) score, age and treatment. Presence of FL-LP was associated with shorter progression-free survival (PFS) and overall survival (OS) (P = 0·004 and P = 0·031, respectively). Presence of FL-LP and high FLIPI score remained independent prognostic factors in a Cox model for time to progression (TTP). A number of circulating lymphoma cells (CLC) >4 × 10(9) /l was the most significant predictor for a shorter TTP in this Cox model. The prognostic impact of FL-LP on TTP was validated in the PRIMA cohort (P = 0·0004). In conclusion, FL-LP is a rare event associated with shorter PFS and patients with CLC >4 × 10(9) /l have a poorer outcome. These patients should be monitored carefully to consider alternative therapeutic options.