An Index Case of Concomitant Tumoral and Ichthyosiform Mycosis Fungoides-Like Presentation of Chronic Adult T-cell Leukemia/Lymphoma Associated With Upregulation of TOX.

Adult T-cell leukemia/lymphoma (ATLL) is a rare and often aggressive lymphoid malignancy known to be associated with human T-cell lymphotropic virus type 1. There are 2 broad categories: acute and chronic. In the acute category, there is a leukemic and a lymphomatous variant, whereas in the designated "chronic" form, there is mild peripheral blood lymphocytosis. The intermediate "smoldering" category is without peripheral blood lymphocytosis with only discernible skin involvement. We present a 68-year-old human T-cell lymphotropic virus type 1 seropositive female with a mild peripheral blood atypical lymphocytosis who had indurated nodules on her hands of 2 years duration and a new scaly ichthyosiform eruption on her lower extremities. Histopathologic examination of the hand biopsy revealed coalescing nodules of large atypical noncerebriform lymphocytes with focal areas of epidermotropism. Phenotypically, the infiltrate was positive for β-F1, CD2, CD4, CD5, CD7, Foxp3, and CD25. In both biopsies, there was striking upregulation of TOX (thymocyte selection-associated high mobility group box factor) in the nuclei of neoplastic cells. The second biopsy taken from the ichthyotic patch on the patient's left leg showed a subtle pattern of epidermal infiltration by atypical noncerebriform lymphocytes and a distinct compact scale consistent with the clinical picture of ichthyosis. The histopathologic appearance was that of a yet undescribed ichthyosiform mycosis fungoides-like presentation of chronic ATLL. In addition, the observed upregulation of nuclear TOX may play an oncogenic role in ATLL. The course to date in this patient has been relatively indolent, although the patients believe that large cell transformation could portend more aggressive disease.