Dermatopathic reaction of lymph nodes in HTLV-1 carriers: a spectrum of reactive and neoplastic lesions.

AIMS: Dermatopathic reaction is a histopathological finding of the lymph node that usually occurs in patients with inflammatory pruritic cutaneous lesions. However, it is sometimes seen in patients with cutaneous T-cell lymphoma. Adult T-cell leukemia/lymphoma (ATLL) is a T-cell malignancy caused by infection with human T-cell leukemia virus type I (HTLV-1), frequently accompanied by cutaneous lesions. However, detailed clinicopathological characteristics of dermatopathic reaction of lymph nodes in ATLL patients and HTLV-1 carriers, addressed in this study, remain to be clarified. METHODS AND RESULTS: We retrospectively analyzed 18 nodal lesions with dermatopathic reaction in human T-cell leukemia virus 1 (HTLV-1) carriers. Axillary and inguinal lymph nodes were the primary affected tissues. Three cases with atypical lymphoid cell infiltration were defined as ATLL with dermatopathic reaction (ATLL-D), showing an abnormal T cell immunophenotype and T-cell monoclonality. Two of the three ATLL-D patients died 14 and 7 months after diagnosis (the third case had a very short follow-up). The other 15 patients were indistinguishable from reactive lesions and were defined as HTLV-1-associated lymphadenitis with dermatopathic reaction (HAL-D). They showed an indolent clinical course, with only one case eventually transforming to aggressive disease. CONCLUSIONS: Lymph node lesions accompanied by dermatopathic reaction in HTLV1 carriers represent a spectrum that includes reactive and neoplastic conditions. HAL-D should be distinguished from ATLL-D, especially to avoid overtreatment.