A study of histologic and immunophenotypical staining patterns in cutaneous lymphoid hyperplasia.

Background: Cutaneous lymphoid hyperplasia (CLH) is generally classified according to clinicopathologic entities or put into broad spectrums of B-cell or T-cell predominance or co-dominance.

Objective: We sought to discern histologic features and immunohistochemical staining patterns in CLH that may form a basis for a histologic classification system.

Methods: We studied the clinical, histologic, immunophenotypical, and molecular characteristics of 24 consecutive patients with CLH.

Results: The 24 cases were classified according to characteristic histologic features and immunophenotypical staining patterns as follows: presence of germinal center (GC) cell clusters forming well-defined lymphoid follicles (n = 10); presence of clusters of GC cell clusters not forming well-defined lymphoid follicles (n = 6); persistent arthropod assault type CLH (n = 1); CLH with a prominent histiocytic component (n = 4); and CLH without specific histologic and immunophenotypical features, that is, nonspecific mixed T-cell and B-cell CLH (n = 3). Most of the CLH cases did not demonstrate clonal T-cell receptor and/or immunoglobulin heavy chain gene rearrangements except for 3 cases in which the long-term follow-up was uneventful.

Limitations: There were a limited number of cases in our study.

Conclusions: A classification based on characteristic histologic features and immunophenotypical staining patterns, along with pertinent clinical and molecular data, may enhance the diagnosis of CLH.