Clinicopathological analysis of the hydroa vacciniforme-like lymphoproliferative disorder with natural killer cell phenotype compared with cutaneous natural killer T-cell lymphoma.

Hydroa vacciniforme-like lymphoproliferative disorder (HVLPD) is defined as a distinctive clinicopathological type of cutaneous lymphoma and a subset of patients with this disease exhibit the natural killer (NK)-cell phenotype. The HVLPD-NK cell phenotype may be difficult to distinguish from cutaneous natural killer T-cell lymphoma (CNKTL), as these two diseases share similar immunophenotypic markers. Therefore, the aim of the present study was to analyze the clinicopathological features of this rare disease and compare these features with those of CNKTL. The clinical, histopathological and molecular features of 5 patients with the HVLPD-NK cell phenotype and 11 patients with CNKTL were evaluated. As well as certain subtle histopathological differences, there marked differences the age, distribution of lesions and clinical course differed between patients with these two diseases. These results suggest that the HVLPD-NK cell phenotype should be classified as a separate disorder and treated accordingly.