Ichthyosiform mycosis fungoides: an atypical variant of cutaneous T-cell lymphoma.

BACKGROUND: Acquired ichthyosis is a known paraneoplastic sign of lymphoproliferative malignancies, with histopathologic findings that are nonspecific, revealing no insinuation of the underlying neoplasm. Ichthyosiform eruption as a specific manifestation of mycosis fungoides (MF), ie, ichthyosiform MF, is, however, regarded as rare and to date has been reported in only a few cases.

OBJECTIVE: We sought to study the clinical, histopathologic, immunohistochemical, and genotypic features of patients with ichthyosiform MF.

METHODS: The files of patients with MF seen during the past 8 years in our department were reviewed to search for cases of ichthyosis-like MF.

RESULTS: Seven patients, comprising 3.5% of the patients seen with MF, had an ichthyosiform eruption with histopathologic features characteristic of early MF. In 2 patients it was the sole manifestation of the disease and in 5 patients it appeared either in conjunction with conventional patches and/or plaques or with follicular lesions. Immunohistochemically, all showed a predominance of CD3+ CD4+, except for 1 patient in whom the epidermotropic T cells were predominantly CD8+. In 3 of the 7 patients clonality could be demonstrated by polymerase chain reaction. None had extracutaneous involvement. All had an indolent course of the disease and responded well to skin-targeted therapies.

CONCLUSIONS: Ichthyosiform MF is yet another atypical clinical variant of cutaneous T-cell lymphoma that is not as rare as reflected in the literature. It may be the sole manifestation of the disease but also may appear in conjunction with conventional or follicular MF lesions.