Immunotopography of splenic lymphoma of small cleaved B-cell type.

Using a battery of monoclonal antibodies on snap-frozen sections, we delineated the immunoarchitecture of two splenic small cleaved cell lymphomas (SCL). Both cases had light- and heavy-chain restricted immunoglobulin (lg) expression signifying replacement of splenic white pulp by a single B-cell clone. Both the monotypia and aberrant topography of lg expression in SCL contrasted with the usual polyclonal, zonal lg expression in reactive splenic B-cell zones. Pan B antigens (B1, B4, and L14) were constant in expression as expected for B-cell neoplasms, while B-cell maturation antigens (B2, IgD, and CALLA) were variably expressed, suggesting that different SCL may derive from separate phases of B-cell ontogeny. Close association of SCL with dendritic reticulum cells suggests SCL may derive from splenic secondary follicles or home to these sites. The variable T-cell component detected by a T-cell panel (Leu 1-9) indicates the substantial range of T-cell reactivity in splenic SCL. We emphasize the immunologic aberrancy of splenic SCL when compared to normal splenic B-cell immunotopography. Further, we illustrate the utility of serial tissue section immunochemistry in revealing complex neoplastic cell phenotypes and in revealing the relationships of reactive cells to neoplastic cells.