Atypical lymphoplasmacytic and immunoblastic proliferation from systemic lupus erythematosus. A case report.

A case of atypical lymphoplasmacytic and immunoblastic proliferation (ALPIBP) in the lymph nodes associated with well-documented systemic lupus erythematosus (SLE) is presented. A 30-year-old Japanese female with an 18-year history of SLE presented with right neck lymphadenopathy of 3 months duration. A biopsy specimen showed a diffuse effaced lymph node architecture without follicles and minimal sinuses. At high power field, a polymorphous population of small- to medium-sized lymphocytes, plasma cells, plasmacytoid cells, as well as large, basophilic transformed lymphocytes and immunoblasts diffusely infiltrated the paracortical area. Interestingly, the immunohistochemical study demonstrated large, irregularly shaped accumulations of follicular dendritic cells (FDCs) surrounding the small vessels, which is an immunohistochemical finding characteristic of angioimmunoblastic T-cell lymphoma (AILT). However, the present lesion showed the following differences to AILT: (a) absence of CD3+, CD4+ and CD10+ clear cells, which are tumor cells of AILT; (b) absence of pronounced arborizing vascular proliferation; (c) on molecular analysis, the present case demonstrated a polyclonal pattern converse to the monoclonal T-cell receptor gamma chain gene rearrangement in most AILTs (d) absence of EBV infected lymphoid cells, which are frequently detected AILT. As previously suggested, the present case indicates that a clinical correlation as well as immunohistologic and genotypic studies may be necessary to discriminate between ALPIBPs and AILT.