[1329] Myelodendritic Cell Neoplasms: A Description of 3 Cases

Anna R Balog, Howard J Meyerson. University Hospitals Case Medical Center, Cleveland, OH

Background: Previously there have been rare reports of Langerhans cell histiocytosis (LCH) associated with myelodysplasia or chronic myelomonocytic leukemia (CMML). We hypothesized that primary myeloid marrow stem cell disorders are associated with myeloid dendritic cell tumors. In this study, we analyze and describe the features of 3 individuals with marrow myeloid stem cell malignancies and co-existing tumors with myeloid dendritic cell differentiation.
Design: The clinical, pathologic and phenotypic features of 3 patients with myelodysplasia or CMML and co-existing tumors with a population of cells expressing CD141 and/or CD1c, antigens indicative of myeloid dendritic cell origin, were reviewed.
Results: Three patients were identified. Patient 1 was a 63 year old man with CMML who developed an aggressive intramedullary tumor of the bone marrow originally classified as histiocytic sarcoma. Phenotyping revealed the lesional cells were of myeloid dendritic cell lineage (CD141+, CD4+, HLA-DR+, CD1a-, CD14- and weakly CD68+). The patient died within 3 months of diagnosis. Patient 2 was a 79 year old man who presented with LCH of the skin, GI tract and spleen and a concurrent unclassifiable low grade myelodysplasia. Two years later the patient developed a highly aggressive tumor of the lymph node morphologically compatible with Langerhans/myeloid dendritic cell sarcoma with a CMML-like picture in the peripheral blood. Phenotyping of the lesional cells of the lymph node and blood was consistent with myeloid dendritic cell lineage (CD141+, CD1c+, CD4+, HLA-DR+, CD1a dim/partial, CD14 dim/negative, and CD68-). The patient died within a week of diagnosis. Patient 3 is a 6 year old boy who presented with hepatosplenomegaly and pancytopenia with blasts and dysplastic granulocytes in the peripheral blood but without a monocytosis. Splenectomy, liver biopsy and bone marrow biopsy demonstrated infiltration by cells with mature dendritic/histiocytic morphology. Phenotyping revealed the lesional cells were a mixture of CD16+ monocytes and myeloid dendritic cells (CD141+, CD1c-, CD4+, HLA-DR+, CD1a-, CD14 dim, and weakly CD68+). The patient is currently being followed.
Conclusions: This study describes 3 patients with myeloid dendritic cell lesions and an associated MDS or CMML. We suggest the name myelodendritic cell neoplasms for this group of disorders.
Category: Hematopathology

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 233, Wednesday Morning


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