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A 61-year-old female presented with increasing shortness of breath and multiple skin lesions on her back and buttocks. The peripheral blood smear showed a leukocyte count as high as 21.7 x 103/µL with frequent circulating highly atypical lymphocytes that demonstrated a wide range of morphologic features including small atypical lymphocytes, “flower-like” cells, and “hallmark cells”. Flow cytometric analysis of the peripheral blood revealed an abnormal T-cell population that expressed CD2, CD3, CD4, CD5, CD30 and CD45 with increased forward and side scatter. They had diminished expression of CD7 without CD8 expression. PCR analysis for T-cell receptor gene rearrangement confirmed the presence of a clonal T-cell population in the peripheral blood. A biopsy of the skin lesions as well as a staging bone marrow biopsy showed sheets of large atypical lymphocytes with the same immunophenotype. The lymphoma cells were negative for ALK by immunohistochemistry. The combined morphologic and phenotypic findings were indicative of ALK-negative anaplastic large cell lymphoma (ALCL). The patient was diagnosed with widespread ALCL involving the bone marrow, peripheral blood, skin, CNS, and pleural fluid. She received a brief course of chemotherapy before her condition deteriorated and she expired one month after her diagnosis. Approximately 15-20% of all cases of ALCL do not have NPM/ALK fusion gene due to a t(2;5) translocation and are termed ALK-negative ALCL. ALK negative ALCL may involve both lymph nodes and extranodal sites such as skin, lung, bone, and soft tissues. Bone marrow involvement is less common (10-30% of cases) and peripheral blood involvement (as seen in this case) is extremely rare. The 2008 WHO classification includes ALK-negative ALCL as a separate entity due to the fact that ALK negative ALCL frequently occurs in an older patient population and has a more aggressive clinical course compared to ALK-positive ALCL. Although uncommon, leukemic phase ALCL is an important differential diagnostic consideration in patients with circulating highly atypical lymphocytes.
ALK-negative anaplastic large cell lymphoma, leukemic phase
#00017922
Author: Changlee S. Pang, A. Citabria Holley
Category: Lymphoma: Mature T and NK cell lymphoproliferations > Mature T-cell Lymphomas > Anaplastic Large Cell Lymphoma, ALK negative
Published Date: 04/17/2013
Category: Lymphoma: Mature T and NK cell lymphoproliferations > Mature T-cell Lymphomas > Anaplastic Large Cell Lymphoma, ALK negative
Published Date: 04/17/2013
A 61-year-old female presented with increasing shortness of breath and multiple skin lesions on her back and buttocks. The peripheral blood smear showed a leukocyte count as high as 21.7 x 103/µL with frequent circulating highly atypical lymphocytes that demonstrated a wide range of morphologic features including small atypical lymphocytes, “flower-like” cells, and “hallmark cells”. Flow cytometric analysis of the peripheral blood revealed an abnormal T-cell population that expressed CD2, CD3, CD4, CD5, CD30 and CD45 with increased forward and side scatter. They had diminished expression of CD7 without CD8 expression. PCR analysis for T-cell receptor gene rearrangement confirmed the presence of a clonal T-cell population in the peripheral blood. A biopsy of the skin lesions as well as a staging bone marrow biopsy showed sheets of large atypical lymphocytes with the same immunophenotype. The lymphoma cells were negative for ALK by immunohistochemistry. The combined morphologic and phenotypic findings were indicative of ALK-negative anaplastic large cell lymphoma (ALCL). The patient was diagnosed with widespread ALCL involving the bone marrow, peripheral blood, skin, CNS, and pleural fluid. She received a brief course of chemotherapy before her condition deteriorated and she expired one month after her diagnosis. Approximately 15-20% of all cases of ALCL do not have NPM/ALK fusion gene due to a t(2;5) translocation and are termed ALK-negative ALCL. ALK negative ALCL may involve both lymph nodes and extranodal sites such as skin, lung, bone, and soft tissues. Bone marrow involvement is less common (10-30% of cases) and peripheral blood involvement (as seen in this case) is extremely rare. The 2008 WHO classification includes ALK-negative ALCL as a separate entity due to the fact that ALK negative ALCL frequently occurs in an older patient population and has a more aggressive clinical course compared to ALK-positive ALCL. Although uncommon, leukemic phase ALCL is an important differential diagnostic consideration in patients with circulating highly atypical lymphocytes.
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