Cutaneous T-cell lymphoma, NK-cell lymphoma, and myeloid leukemia

Chapter 24

Cutaneous T-cell lymphoma, NK-cell lymphoma, and myeloid leukemia

Cutaneous T-cell lymphoma and NK-cell lymphoma

Mycosis fungoides

Patch stage

Mycosis fungoides (MF) is the most common type of cutaneous lymphoma. In most cases, the disease is indolent and slowly progressive over a period of years or decades. Three main stages of the lymphoma are recognized: patch, plaque, and tumor stages. In the patch stage of mycosis fungoides, patients typically present with broad pink or tan oval-shaped patches with a predilection for the bathing trunk area. The patches may be asymptomatic or pruritic. Both clinically and histopathologically, distinction from eczematous dermatitis is sometimes difficult in the earliest stages of the lymphoma. In the evaluation of patch stage mycosis fungoides, multiple shave biopsies are often helpful, since the shave technique provides a broad area of epidermis for examination. The typical immunophenotype is CD3+, CD4+, CD8−, CD30−. Aberrant immunophenotypes (with loss of normal T-cell markers, such as CD7) can frequently be demonstrated. Clonal rearrangement of the T-cell receptor gene is helpful in supporting the diagnosis, although the earliest cases may sometimes not have a detectable clone.

Granulomatous slack skin

Granulomatous slack skin syndrome is an extremely rare variant of mycosis fungoides with a slowly progressive clinical course. The clinical presentation is striking. In fully developed cases, massive folds of skin extend from flexural areas, such as the axillae or groin. An association with nodal Hodgkin lymphoma has been documented in multiple cases.

Sézary syndrome

Although previously believed to be a leukemic variant of mycosis fungoides, Sézary syndrome is now considered to originate from a different subset of T cells (central memory T cell in Sézary syndrome versus skin resident memory T cell in mycosis fungoides). In contrast to mycosis fungoides, Sézary syndrome has a rapidly progressive clinical course and a poor prognosis. The diagnosis is confirmed by evaluation of the peripheral blood. Skin biopsy is sometimes useful in demonstrating a histopathologic pattern similar to mycosis fungoides. It should be recognized, however, that skin biopsy findings may be non-diagnostic in some cases of Sézary syndrome. In an erythrodermic patient, non-specific biopsy findings (such as spongiotic dermatitis) do not exclude the diagnosis. It is important to evaluate the peripheral blood if there is clinical suspicion for Sézary syndrome.

Adult T-cell leukemia/lymphoma (ATCLL)

Adult T-cell leukemia/lymphoma is remarkable for its well-established viral etiology, i.e. human T-cell leukemia virus type 1 (HTLV-1

Apr 26, 2016 | Posted by in Dermatology | Comments Off on Cutaneous T-cell lymphoma, NK-cell lymphoma, and myeloid leukemia
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