Recent advances in mastocytosis and neoplasms of probable monocytic/dendritic cell lineage

Does the Aberrant Expression of CD2 and CD25 by Skin Mast Cells Truly Correlate with Systemic Involvement in Patients Presenting with Mastocytosis in the Skin?

“…In addition, multiple recent and past studies have described the BMMC immunophenotype in detail [11][12][13][14][15][16] . In contrast, little is known about the immunophenotypic profile of skin MCs (sMCs) in patients with mastocytosis [17][18][19][20] . It has been reported that sMCs in mastocytosis patients may coexpress CD25 and CD4 but do not express CD2.…”

“…It has been reported that sMCs in mastocytosis patients may coexpress CD25 and CD4 but do not express CD2. However, it has to be stressed that those studies were based on small groups of patients [17,19,20] . Furthermore, the frequency of CD2 and CD25 expression on sMCs has never been assessed in CM and SM patients, who were diagnosed strictly according to the WHO criteria.…”

Tumorous proliferations of plasmacytoid dendritic cells and Langerhans cells associated with acute myeloid leukaemia

“…In particular, tumour‐like proliferation of PDCs in lymph nodes or extranodal sites, associated with myeloid neoplasms, such as chronic myelomonocytic leukaemia, acute myeloid leukaemia, and myelodysplastic syndrome, has been described in several reports 9–13 . Langerhans cells (LCs) constitute a well‐defined conventional DC subset that is largely confined to the epidermis and squamous mucosa, and they uniquely express CD1a, langerin, and cytoplasmic HLA‐DR (MHC‐II), but not fascin 2,14 . It is likely that interdigitating DCs are simply interstitial DCs and LCs that have migrated to the lymph nodes from peripheral tissue and have undergone maturation 14 .…”

“…[9][10][11][12][13] Langerhans cells (LCs) constitute a well-defined conventional DC subset that is largely confined to the epidermis and squamous mucosa, and they uniquely express CD1a, langerin, and cytoplasmic HLA-DR (MHC-II), but not fascin. 2,14 It is likely that interdigitating DCs are simply interstitial DCs and LCs that have migrated to the lymph nodes from peripheral tissue and have undergone maturation. 14 LC histiocytosis (LCH), a neoplastic proliferation of LCs, is well known and not uncommon.…”

Solitary mastocytoma in the eyelid of an adult

“…Mastocytosis is a neoplastic proliferation of mast cells that can present in the skin with or without systemic disease. 1 , 2 , 3 It is sub-classified according to microscopic and clinical features, including sites of involvement and clinical behavior. 1 , 2 , 3 Clinical variants include cutaneous mastocytosis; indolent systemic mastocytosis; systemic mastocytosis with associated clonal hematological non-mast-cell lineage disease; aggressive systemic mastocytosis; mast cell leukemia; mast cell sarcoma; and extracutaneous mastocytoma.…”