Tumorous proliferations of plasmacytoid dendritic cells and Langerhans cells associated with acute myeloid leukaemia.
OBJECTIVE
Proliferation of plasmacytoid dendritic cells (PDCs) occurs in both reactive lymphoid hyperplasia and myeloproliferative disorders, especially chronic myelomonocytic leukaemia. PDCs in the former appear reactive, but in the latter are reported to be clonally related to the underlying myeloid neoplasm. Langerhans cells (LCs), another type of dendritic cell, also proliferate in both reactive dermatoses and, rarely, myeloproliferative disorders, such as acute leukaemia.


RESULTS
We report a rare case of tumorous proliferation of PDCs and LCs in the systemic lymph nodes in a 55-year-old man with acute myeloid leukaemia. A microsatellite instability assay showed identical patterns of short tandem repeats in both microdissected PDC and LC components, along with blood blasts.


CONCLUSIONS
We hypothesize that the combined proliferations of PDCs and LCs derive from the same haematopoietic stem cells, but that they differentiate divergently under the effect of different microenvironments.
Department of Pathology, National Cheng Kung University and Hospital, Tainan, Taiwan.
Hsiang-Lin
HL
Song
Wen-Ya
WY
Huang
Ya-Ping
YP
Chen
Kung-Chao
KC
Chang
D015703:Antigens, CD / Q000378:metabolism; D001752:Blast Crisis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D001854:Bone Marrow Cells / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007801:Langerhans Cells / Q000378:metabolism / Q000473:pathology*; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D053842:Microsatellite Instability; D018895:Microsatellite Repeats; D008875:Middle Aged
D015703:Antigens, CD