Ichthysosiform patch stage mycosis fungoides

There is a limited body of literature precedence on ichthyosiform mycosis fungoides. It is an atypical clinical variant that represents less than 5% of patients with mycosis fungoides in some series. The hallmarks were an ichthyosiform eruption with histopathologic features of early mycosis fungoides with the ichthyosiform quality being reflective both clinically and light microscopically.

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Slide 1: The patient is a 35 year old male who presents with a fish scale-like eruption on the thigh characterized by coalescing patches. The biopsy shows a epidermotrophic lymphocytic infiltrate associated with an ichthyosiform thickened stratum corneum, manifesting compact orthohyperkeratosis.

Slide 2: There is colonization of the basal layer by atypical lymphocytes, and as well, there is a haphazard pattern of lymphocyte migration above the basal layer. The cells are disposed singly and in small aggregates.

Slide 3: The lymphocytes are hyperchromatic showing significant nuclear contour irregularity, including cells that have a hyperconvoluted cerebriform appearance.

Slide 4: There is highlighting of the epidermotropic lymphocytic infiltrate for the pan T cell marker CD2.

Slide 5: There is highlighting of the epidermotropic lymphocytic infiltrate for the pan T cell marker CD3.

Slide 6: In examining CD5, however, there is a decrement in staining relative to the other pan T-cell markers, probably in the 50% realm.

Slide 7: There is a profound diminution in staining for CD7. Very few lymphocytes within the epidermis stain positively, while around 20% or so of the dermal infiltrate is positive. The intraepidermal reduction is in excess of 90%.

Slide 8: The CD4 preparation highlights intraepidermal monocyte-derived dendritic cells, but the neoplastic cells are negative.

Slide 9: Very few intraepidermal lymphocytes are positive for CD8.

Slide 10: The CD30 preparation shows only a few positive-staining cells defining less than 5% of the infiltrate.