Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma (CTCL), and MF is a malignant lymphoma that's characterized by the expansion of a clone of the CD4⁺ (or helper) memory T cells that frequently lacks other normal T-cell antigens (CD7). The skin rash in MF patients usually consists of patches, plaques or tumors that may have a long natural history; however many atypical variants have also been reported1. The MF patients with malignancy sometimes have ichthyosis. Ichthyosiform eruption as a specific manifestation of MF is very rare and this represents 1.8% of all MF cases. Only a few cases of ichthyosiform eruption as a specific manifestation of MF have currently been reported in the English literature1-8. We report here on the case of a 63-year-old Korean man who presented with ichthyosiform eruption and a histological pattern of MF.

A 63-year-old Korean man had a 4-year history of a pruritic eruption. There was no personal or family history of ichthyosis or atopy. The ichthyosiform skin changes were widespread, but they were mainly located on the abdomen, arms, thighs and shins (Fig. 1). The face, palms, soles and most flexure areas were spared. Yet it was interesting that we did find a finely scaled eruption on the axilla. There was no peripheral lymphadenopathy or organomegaly. The typical lesions of MF were not present. The results of the routine investigations were normal or negative, including the complete blood count, the differential leukocyte count, the erythrocyte sedimentation rate and the blood chemistry studies. Antinuclear antibodies were not detected. The serologic studies were negative for HIV. No Sézary cells were present in the peripheral blood. Chest x-ray examination, gastroscopy and proctoscopy revealed no abnormalities. A skin biopsy specimen from the ichthyosiform lesion on the abdomen revealed parakeratosis and focally compact orthokeratosis of the epidermis with an underlying thinned granular layer. In the superficial dermis, there was a lichenoid infiltrate that mainly consisted of lymphocytes and histiocytes and it also showed epidermotrophism and microabscess (Fig. 2). The lymphocyte nuclei were hyperchromatic and cerebriform. Immunostaining confirmed the T cell helper pattern of the dermal and epidermal lymphocytes (CD2+, CD3+ and CD4+, but CD20- and CD30-). To assess the clonality in the paraffin-embedded samples, polymerase chain reaction single-strand conformational polymorphism (PCR-SSCP) was performed as previously described9 to detect T-cell receptor γ (TCR-γ) gene rearrangements. On the results, a monoclonal T-cell clone was detected in the ichthyosiform skin lesion (Fig. 3). Genomic DNA was obtained from the 5-µm sections of the formalin-fixed paraffin-embedded tissues by dewaxing with xylene, proteinase K digestion and phenol/chloroform extraction. The DNA was precipitated in ethanol, dried and dissolved in distilled water. Vγ1-8, Vγ9, Vγ10, Vγ11 and Jγ1/Jγ2 consensus primers were used and the PCR products were analyzed by SSCP combined with 20% polyacrylamide gel electrophoresis. A chronic nonspecific dermatitis sample was used as a polyclonal control.

The diagnosis of Mycosis fungoides stage Ib (T2N0M0) was established. The patient was treated with twice weekly PUVA photochemotherapy for 3 months, and the ichthyosiform eruption regressed.

In general, MF is a slowly progressing chronic disorder. It usually begins as flat patches, which may or may not be histologically diagnosed as MF. Many variations of MF have been described, such as the follicular, granulomatous, hypo- or hyperpigmented and unilesional varients1. Moreover, ichthyosis-like eruption may very rarely be the first sign of MF. Acquired ichthyosis is recognized as one of the cutaneous manifestations of malignancies9. A few cases have recently been reported in which the ichthyosiform eruption proved to be a specific manifestation of MF2-8.

Acquired ichthyosis may develop in patients of any age and who have several systemic diseases. It has occurred in association with Hodgkin's lymphoma, non-Hodgkin's lymphoma, MF, multiple myeloma and carcinomatosis. Ichthyosiform MF differs from acquired ichthyosis associated with cutaneous lymphoma10. In the latter condition, the patient presents with both the cutaneous specific lesions of lymphoma and ichthyosis. However, a skin biopsy of the ichthyotic lesions does not show any pathologic aspect of lymphoma, but rather, it shows only epidermal hyperplasia. In the former condition, on the other hand, ichthyosis can be the only clinical manifestation of MF, and the histologic findings are consistent with both ichthyosis and MF as well. According to the clinical findings, ichthyosiform MF can be divided into 3 types: 1) ichthyosiform eruption as the sole manifestation of the disease, 2) ichthyosiform eruption in conjunction with additional atypical findings of MF and 3) ichthyosiform eruption in combination with the classic types of MF. To date, 5 cases4,6-8 that showed ichthyosiform eruption as the sole manifestation of MF have been reported (Table 1). Our patient also had the sole manifestation of ichthyosiform MF. Clinical remission in such cases is obtained with nonaggressive therapies such as topical treatments, PUVA therapy and ultraviolet light B (UVB)6.

Acquired ichthyosis can either indicate the presence of a severe underlying disease or it reveals an atypical form of cutaneous T cell lymphoma. Thus, the patients with acquired ichthyosis should be carefully evaluated by performing a through biopsy.