Eosinophilic dermatosis of hematologic malignancy: Correlation of molecular characteristics of skin lesions and extracutaneous manifestations of hematologic malignancy.

ABSTRACT

BACKGROUND: Skin diseases are frequent in patients with chronic lymphocytic leukemia (CLL) and other hematological neoplasias. Eosinophilic dermatosis (ED) of hematologic malignancy has long been considered a nonspecific cutaneous reaction pattern. Recently neoplastic cells have been shown to be present in ED, thus challenging the classification as a nonspecific dermatosis. METHODS: We report five patients with ED in association with CLL. We further investigated the presence of neoplastic B-cells in the skin infiltrate by immunohistochemistry and immunoglobulin heavy chain rearrangement and compared these to extracutaneous manifestations of CLL. RESULTS: The phenotype of the lymphocytic infiltrate was predominately CD3+ (range 60%-90%). CD20+ and CD79a+ lymphocytes were less frequent, accounting for up to 15% (range absent - 15%). CD23+ lymphocytes represented up to 20% (range absent - 20%) of the infiltrate. The analysis of the immunoglobulin heavy chain rearrangement in the skin specimens showed clonal rearrangements in 4/5 patients and in three of these four patients clones were identical to extracutaneous CLL manifestations. CONCLUSION: Our data show that neoplastic B-cells are very frequently found in ED when systematically evaluated. This findings support the hypothesis that leukemic cells play a pathogenetic role in ED of hematologic malignancy.