North Texas Research Forum 2025
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Division
North Texas
Hospital
Medical City Fort Worth
Specialty
Dermatology
Document Type
Poster
Publication Date
2025
Keywords
T cell lymphoma, lymphoma, CTCL, differential diagnosis
Disciplines
Dermatology | Medicine and Health Sciences | Neoplasms
Abstract
Introduction Cutaneous T cell lymphoma (CTCL) is a rare, cutaneous, malignant neoplasm of the resident T cell lymphocytes within the skin. CTCL encompasses a spectrum of morphologically and prognostically distinct entities, the most common of which is mycosis fungoides (MF). The incidence of mycosis fungoides is about 6 cases per million per year in the United States and Europe. MF is notoriously difficult to diagnose clinically. It can masquerade as several common dermatologic conditions and may be treated as such for years until a biopsy reveals the correct diagnosis. One of the most common diseases that MF mimics is atopic dermatitis (AD). Severe atopic dermatitis and MF share overlapping distributions and similar morphologies. Here we present cases illustrating the differences and similarities between Mycosis Fungoides and Atopic Dermatitis. Case Presentation A 54-year-old Fitzpatrick II (mostly burns, rarely tans) female demonstrates patch/plaque stage mycosis fungoides shown in Figure 1. There are pink to erythematous patches and thin plaques in non-sun-exposed areas, known as a “bathing suit” distribution. There is also notable poikiloderma with hyperpigmentation, hypopigmentation, skin atrophy, and telangiectasias. In Figure 2, a Fitzpatrick VI (never burns, always tans) male displays erythrodermic mycosis fungoides. There is generalized erythema with diffuse overlying hyperkeratotic papules coalescing into scaly plaques. Figure 3 shows a 38-year-old Fitzpatrick IV (rarely burns, mostly tans) male with chronic atopic dermatitis and secondary lichen simplex chronicus. There are lichenified plaques with overlying linear erosions suggestive of scratching. Learning Points MF classically presents as hyper and hypopigmented mottled patches or plaques with telangiectasias involving atrophic skin. The rash is caused by a clonal population of atypical, malignant T cell lymphocytes. It presents in sun spared areas, known as a “bathing suit distribution” because the malignant T cells are sensitive to ultraviolet light. In the early stages, the skin may appear xerotic, or dry and flaky. This makes active areas of MF difficult to distinguish from normal skin or atopic dermatitis. AD is much more common, affecting approximately 7 % of adults in the United States. It classically begins in childhood and can involve the hands, feet, trunk and flexural surfaces. It typically presents as dry, erythematous to hyperpigmented plaques with or without lichenification. It is important to consider mycosis fungoides in the differential diagnoses for any longstanding eczematous rash that is resistant to common therapies for atopic dermatitis and clinical suspicion should prompt a skin biopsy.
Original Publisher
HCA Healthcare Graduate Medical Education
Recommended Citation
Scheufele, Christian; Loux, Paige; Lim, Henry; Furth, Garrett; Hall, Marshall; Carletti, Michael; and Weis, Stephen, "Mycosis Fungoides: A Mimicker of Atopic Dermatitis" (2025). North Texas Research Forum 2025. 47.
https://scholarlycommons.hcahealthcare.com/northtexas2025/47