Significance of non-lymphoid ('accessory') cells in malignant lymphomas and pseudolymphomas of the skin

Abstract

We investigated the co-distribution of lymphocyte subpopulations and non-lymphoid 'accessory' cells in 35 cases of cutaneous lymphoproliferative diseases (T-cell lymphoma, 10 cases; B-cell lymphoma, 17 cases; pseudolymphoma, 8 cases) using immunohistochemical methods. T-zone histiocytes and particularly Langerhans cells were abundant in all cutaneous T-cell lymphomas, but were also found in B-cell lymphomas. T-zone histiocytes were associated with T-lymphocytes, especially T-helper cells, but not with T-suppressor cells. Dendritic reticulum cells were essentially confined to well differentiated germinal centres. Macrophages occurred in both lymphomas and pseudolymphomas without definite relationship with either B- or T-cells. In malignant lymphomas of high grade malignancy, macrophages represented the only non-lymphoid cell type. Our results indicate that malignant lymphoid cells, like normal lymphocytes, require definite micro-environments which are, at least in part, maintained by certain non-lymphoid cells.

Immunohistochemical classification of cutaneous pseudolymphomas: delineation of distinct patterns

“…A follicular B cell pattern with polyclonal light chains proves the diagnosis of a pseudolymphoma. A similar pattern may be observed in centroblastic-centrocytic lymphoma (45), but will usually be associated with monoclonal light chains. In case of polyclonality, reactive germinal centers within a malignant lesion, however, will have to be excluded by careful observation of tbe overall pattern and tbe cytologic features.…”

“…Tbe non follicular B cell pattern bas to be diflerentiated from specific infiltrates in cbronic lymphocytic leukemia. The expression of CD 5 on the B cells of the latter disease will help to distinguish both entities (45). The nodular T cell pattern, which usually reveals small nodular dermal infiltrates, can be separated from cutaneous T cell lympboma by histological features and the low proliferation rate (47).…”

Study of the reactive dendritic cells in small B-cell lymphoproliferations of the skin

“…Moreover, in T-cell infiltrates, they noted different DC distributions in malignant and inflammatory infiltrates, with larger, more loosely arranged DC aggregates seen in malignant lesions. Smolle J et al [14] investigated the distribution of non-lymphoid accessory cells in 35 lymphoproliferative disease specimens using Fig. 4 Immunolabeling of anti FXIIIa.…”

“…Macrophages in cutaneous infiltrates have not been extensively studied. Only one study showed that macrophages are more numerous in CLH than in B-or T-cell lymphoma [14].…”

“…Reactive cells are known to be frequent in LG-pCBC [8,14] and often mask tumor cells. They comprise small T lymphocytes and cell of the histiocyte lineage [macrophages and dendritic cells (DC)].…”