Derm Dx: Skin Rash on the Abdomen, Flank, and Upper Thigh

Mycosis fungoides (MF) is the most common and classic form of cutaneous T-cell lymphoma. The disease often appears in mid- to late-adulthood and is twice as common in men compared with women. The incidence is highest in African American patients....

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Mycosis fungoides (MF) is the most common and classic form of cutaneous T-cell lymphoma. The disease often appears in mid- to late-adulthood and is twice as common in men compared with women. The incidence is highest in African American patients. The malignant cells in this disease are epidermotropic peripheral T lymphocytes.¹

MF usually progresses in severity from patch to plaque and, ultimately, tumor stage.² The disease in the patch stage presents as nondescript macules that may possess a fine scale. Color changes are often minimal although some cases demonstrate striking hypo- or hyperpigmentation. Differential diagnoses include common conditions such as eczema, psoriasis, and tinea. Psoriasis-like lesions appear in plaque stage. Over time, the disease evolves into ulcerated or fungating tumors. 

Early MF is difficult to diagnosis both clinically and histopathologically given the similarity to less serious skin disorders.  The course of the disease varies; some patients succumb within a few years of diagnosis whereas others may live for decades without progression to internal organs or development of cutaneous tumors. Ultrapotent topical steroids, topical nitrogen mustard, and phototherapy are standard therapies for early disease.³ In 2018, the FDA approved mogamulizumab-kpkc, a humanized monoclonal antibody directed against CC chemokine receptor 4, as therapy for relapsed or refractory MF.⁴

Lauren Ax, PA-S, is a student at Arcadia University, and Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, as well as an associate professor of medicine at Commonwealth Medical College and a clinical instructor of dermatology at Arcadia University and Kings College.

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References

1. Jawed SI, Myskowski PL, Horwitz S, Moskowitz A, Querfeld C. Primary cutaneous T-cell lymphoma (mycosis fungoides and Sézary syndrome): part I. Diagnosis: clinical and histopathologic features and new molecular and biologic markers. J Am Acad Dermatol. 2014;70(2):205.e1-16;quiz 221-2.
2. Wolff K, Johnson RA, Saavedre AP Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. 7th ed. New York, NY: McGraw-Hill Companies, Inc; 2013.  
3. Trautinger F, Eder J, Assaf C, et al. European Organisation for Research and Treatment of Cancer consensus recommendations for the treatment of mycosis fungoides/Sézary syndrome-Update 2017. Eur J Cancer. 2017;77:57-74.
4. Nelson R. FDA approved new drug for cutaneous T-Cell lymphomas. Medscape website. https://www.medscape.com/viewarticle/900439. Published August 8, 2018. Accessed December 18, 2018.