Evidence for a lymphotropic nature of circulating plasmacytoid monocytes: findings from a case of CD56+ chronic myelomonocytic leukemia

Abstract

Because the cells previously designated plasmacytoid T cells share major immunophenotypic features with cells of the mononuclear‐phagocyte system, they have been re‐named and are now known as plasmacytoid monocytes (PM). We describe a unique case of chronic myelomonocytic leukemia with circulating PM. The patient, a 48‐year‐old man, presented initially with refractory anemia. Four years later his general condition deteriorated, accompanied by an increase in leukocytes to 200 000/μl blood. The bone marrow histology was interpreted as compatible with a diagnosis of chronic myelomonocytic leukemia. Two months before he died, the patient developed generalized lymphadenopathy clinically simulating malignant lymphoma. Histologic examination of an axillary lymph node revealed diffuse infiltration by PM. The PM in the lymph node and some circulating cells closely resembling PM expressed L‐selectin, a finding that could be interpreted as a morphologic correlate of their marked lymphotropism. The detection of large numbers of CD56/CD33 double‐positive circulating blast cells by FACS analysis strongly supported the diagnosis of a leukemia of myelogenous origin. The patient died of tumor cachexia. Autopsy revealed widespread leukemic infiltrates (always containing clusters of PM) in bone marrow, spleen, liver, lymph nodes, and mucosa‐associated lymphoid tissue of the oropharynx. The final diagnosis was one of chronic myelomonocytic leukemia with marked lymphotropism and partial differentiation towards PM. We consider that the rare instances of a hematologic tumor with differentiation towards PM should be classified amongst the myelogenous leukemias.

Clinicopathological features and prognostic significance of CXCL12 in blastic plasmacytoid dendritic cell neoplasm

“…53,54 In our series, we found that only 5 of 23 cases (21.7%) of BPDC were positive for CLA. In the literature, at least 50 BPDC cases (about 10% to 20% of all BPDC cases) demonstrated a transformation to myelomonocytic chronic and AML, 2,6,7,11,27,30,37,[55][56][57][58][59][60][61] although to our knowledge no transformation of BPDCs to ALL has been reported.…”

CD4+/CD56+ Hematodermic Tumor

“…51,105 The induction of phenotypic and functional properties of monocytic DCs in vivo has also been described for tumor cells derived from AML and juvenile myelomonocytic leukemia. 112,113 Horny et al 114 reported a case that progressed from MDS to CMML with marked lymphotropism and atypical clusters of pDC-differentiated cells.…”

A unique case of a myelodysplastic/myeloproliferative neoplasm with distinct histiocytic and dendritic cell outgrowths

“…Approximately 10 to 20 % of cases are associated with hematologic malignancies such as myelodysplastic syndrome, chronic myeloid leukemia, chronic myelomonocytic leukemia, and acute myeloid leukemia [50]. Furthermore, in patients with chronic myelomonocytic leukemia, nodal proliferations of plasmacytoid dendritic cells (originally called plasmacytoid T or BT-zone^cells, and then plasmacytoid monocytes), have been recognized for over two decades [51][52][53][54]. Interestingly, when the skin is involved in CMML, about half the cases have infiltrates showing plasmacytoid dendritic cell lineage [55].…”