Ichthyosiform eruptions in association with primary cutaneous T-cell lymphomas

Background Malignant lymphoma is occasionally complicated by ichthyosiform eruptions. Objectives To analyse histopathologically the ichthyosiform eruptions associated with cutaneous lymphomas. Methods We reviewed the files of patients with malignant lymphoma seen in our dermatology department between January 2001 and May 2006 to search for patients with ichthyosiform eruptions. Results In our series, nine of 106 patients with malignant lymphomas had ichthyosiform eruptions during their clinical courses, including three (30%) of 10 patients with anaplastic large cell lymphoma (ALCL) and six (14%) of 44 patients with mycosis fungoides (MF). None of the 18 patients with cutaneous B-cell lymphoma had ichthyosiform eruptions. The three patients with ALCL had ichthyosiform eruptions histopathologically consistent with acquired ichthyosis (AI) in which packed horny layers and thin granular layers were present without lymphocytic infiltration. In contrast, four of the six patients with MF (stages Ib and IIb) had ichthyosiform eruptions with epidermotropic infiltration of atypical lymphocytes, as observed in ichthyosiform MF (IMF). Of the remaining two patients, one showed histopathological features overlapping AI and IMF, and the other had AI alone. These two patients (stages IVa and IIb) had tumours composed of CD30+ cells. Filaggrin expression was markedly diminished in both AI and IMF-like eruptions, similar to that of inherited ichthyosis vulgaris. Conclusions Ichthyosiform eruptions are often associated with ALCL and MF and can be classified into three groups: AI associated with ALCL and MF expressing CD30, IMF, and their overlap.