The Histopathological Spectrum of Pseudolymphomatous Infiltrates in Cutaneous Lupus Erythematosus
The occurrence of pseudolymphomatous infiltrates in cutaneous lupus erythematosus (cLE) is described mainly in lupus panniculitis and lupus tumidus/lymphocytic infiltration of the skin (Jessner–Kanof). We collected 15 cases of pseudolymphomatous cLE other than lupus panniculitis and lupus tumidus (M:F = 4:11; age range: 23–79 years; mean age: 50.9 years; median age: 57 years). Of the 15 cases, 9 (60%) were characterized by dense nodular infiltrates. Three cases (20%) showed an angiocentric pattern with cytological atypia of lymphoid cells; 2 cases (13.3%) showed a band-like infiltrate mimicking mycosis fungoides, and 1 case had mixed features of the band-like and angiocentric patterns. Clues to the histopathological diagnosis of cLE were presence of interface dermatitis, clusters of plasmacytoid dendritic cells, and dermal mucin deposition. Our study shows that the spectrum of pseudolymphomatous presentations of cLE is broader than previously described, including band-like cases that may be misconstrued as mycosis fungoides, and angiocentric cases that may be misinterpreted as an aggressive lymphoma. Recognition of such cases is possible only on careful clinicopathologic correlation and requires a high level of histopathological suspicion to allow a correct diagnosis and the proper management of the patients.