Subcutaneous panniculitis-like T-cell lymphoma with overlapping clinicopathologic features of lupus erythematosus: coexistence of 2 entities?

We observed 5 patients with subcutaneous panniculitis-like T-cell lymphoma (SPTCL) who were unusual, in that they also exhibited features of lupus erythematosus (LE). This observation is in keeping with a recent study that reported an increased rate of autoimmune disease, including systemic lupus erythematosus (SLE), among patients with SPTCL. In all cases, attributes indicating SPTCL included an infiltrate of lymphocytes with pleomorphic nuclei involving subcutaneous lobules exhibiting a cytotoxic T-cell (CD3/CD8/betaF1) immunophenotype. Additionally, a high proliferation rate and a monoclonal T-cell receptor-gamma gene rearrangement were observed in most cases. The manifestations of LE in these patients included a spectrum of clinical and histopathological abnormalities. Clinical manifestations of LE included, in some patients, morphologic evidence of lupus erythematosus panniculitis (LEP) with subcutaneous nodules that healed with lipoatrophy on the face. In addition, all the patients exhibited serologic and/or extracutaneous end-organ abnormalities seen in patients with SLE, with 2 patients having sufficient findings to meet American College of Rheumatology criteria for SLE. Histopathological evidence of LE included vacuolar change at the dermal-epidermal interface in 3 patients, 2 of whom also showed interstitial deposition of mucin in the reticular dermis. One of these patients also had findings of LEP in the subcutaneous lobules with clusters of CD20 B cells partially arranged within germinal centers. In 2 patients in which neither the epidermis nor dermis was available for review, histopathological features of LE included, in one patient, a few small clusters of CD123 plasmacytoid dendritic cells within the adipose tissue and, in the other patient, a positive direct immunofluorescence test (lupus band) on clinically uninvolved and lesional skin. Our study shows that some patients show overlap between SPTCL and LE. We suspect that these patients may suffer from both diseases concomitantly. Furthermore, patients with LE, particularly LEP, should be monitored for evolution into SPTCL with biopsy of any subcutaneous lesion that is not typical of LEP. Additionally, screening for cutaneous LE and SLE could be considered in patients with SPTCL.