Mycosis Fungoides

Charles M. Matthews and Eli Glatstein

Background

What subtypes of disorders are encompassed in the general term cutaneous T-cell lymphoma?

Subtypes of cutaneous T-cell lymphoma:

Mycosis fungoides (MF)
Sézary syndrome
Adult T-cell leukemia/lymphoma
Primary cutaneous CD30 anaplastic lymphoma

The following are sometimes considered under the umbrella term of cutaneous T-cell lymphoma:

Lymphomatoid papulosis
Pagetoid reticulosis
Follicular mucinosis

MF comprises what % of all lymphomas?

MF comprises ~2% of all lymphomas but is the most common type of primary cutaneous lymphoma.

What is the median age at presentation in MF?

The median age at presentation of MF is 55–60 yrs.

Is there a race and gender predilection for MF?

Yes. Black race (2:1) and male gender (2.2:1) are known risk factors for having MF.

To what do MF pts have an increased susceptibility?

MF pts have an increased susceptibility to infections and other malignancies, possibly due to an impaired immune system.

What is the histo-pathologic hallmark of MF?

The histopathologic hallmark of MF is the Pautrier abscess (sometimes called microabscess), which refers to the clustering of CD4 T cells around an antigen-presenting dendritic cell in the epidermis. While this is a classic MF finding, it is present in only 20% of early-stage Dz.

What molecular study can be done to Dx early MF?

PCR for the T-cell receptor has been effective at identifying a malignant T-cell clone population in those who go on to develop MF.

What is the most common presentation of early MF?

The most common presentation of early MF is the presence of an erythematous, scaly, and pruritic lesion on an area of skin not commonly exposed to the sun.

What are the clinical presentations/phases of MF?

Clinical presentations/phases of MF:

Premycotic (erythematous macule) phase
Patch phase
Plaque phase
Tumor phase
Erythroderma (>80% surface area involvement)

When MF progresses from patch to plaque, what is seen under the microscope?

When MF progresses from patch to plaque, it is apparent that the lymphoid clones begin to invade deeper into the dermis and the Pautrier abscesses are seen.

What % of MF pts have LN involvement of Dz?

~15% of MF pts have LN involvement of their Dz.

What is a Sézary cell?

Sézary cells are defined as malignant T cells with hyperconvoluted cerebriform nuclei.

What is Sézary syndrome?

Sézary syndrome is an aggressive T-cell lymphoma with the presence of erythroderma + a Sézary cell count ≥100 cells/μL, CD4 to CD8 ratio ≥10, chromosomal T-cell clones that are abnl, T-cell clone detected in the bloodstream with an abnl T-lymphocyte count, and abnl expression of pan T-cell markers (CD2, -3, -4, -5). It sometimes is considered a leukemic form of Dz.