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An Unusual Hematologic Malignancy Derived from Plasmacytoid Dendritic Cells
Author(s) -
Kim J.C.,
Peters S.B.,
Frizzera G.,
McNutt N.S.
Publication year - 2005
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/j.0303-6987.2005.320dp.x
Subject(s) - pathology , plasmacytoid dendritic cell , interleukin 3 receptor , bone marrow , myeloid , malignancy , medicine , dermis , leukemia , dendritic cell , immunology , antigen
Recently reported cases of CD4+ CD56+ hematologic malignancies with a strong predilection for the skin correspond to the neoplastic counterpart of plasmacytoid dendritic cells. This rare, aggressive malignancy lacks pan‐myeloid and pan‐lymphoid markers and often presents with cutaneous lesions, splenomegaly, and involvement of lymph nodes and bone marrow. It has a poor prognosis, and many patients progress to acute myeloid leukemia. The proposed cellular origin is a CD56+ precursor cell related to plasmacytoid monocytes, which strongly expresses CD123 (IL‐3Ra). We describe a 70 year‐old man who presented with gray‐brown truncal nodules and plaques, lymphadenopathy, and splenomegaly. His bone marrow demonstrated malignant CD4+ CD56+ mononuclear cells. Histologic sections of skin lesions showed an atypical infiltrate extending into the deep reticular dermis. Immunohistochemical staining of these cells for CD4 was diffusely positive. Moreover, the infiltrate strongly expressed CD56 and CD123 but showed only patchy or negative staining for other T and B cell markers. The combination of the patient’s clinical presentation and biopsy results best fits the diagnosis of this newly characterized, distinct clinicopathologic entity described in recent literature as agranular CD4+ CD56+ hematodermic neoplasm, plasmacytoid dendritic cell acute leukemia, and tumor‐forming accumulations of plasmacytoid monocytes associated with myeloid disorders.