Dermatologica Sinica

: 2022  |  Volume : 40  |  Issue : 3  |  Page : 192--193

Folliculotropic mycosis fungoides successfully treated with bath psoralen plus ultraviolet a therapy

Yu-Ting Hung1, Meng-Sui Lee1, Tai-Chung Huang2, Su-Ying Wen1, Ruey-Yi Lin3, I-Ling Liu3,  
1 Department of Dermatology, Taipei City Hospital, Taipei, Taiwan
2 Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
3 Department of Dermatology, Taipei City Hospital; Department of Dermatology, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan

Correspondence Address:
Dr. I-Ling Liu
Department of Dermatology, Taipei City Hospital, No. 33, Sec. 2, Zhonghua Road, Zhongzheng District, Taipei City 100

How to cite this article:
Hung YT, Lee MS, Huang TC, Wen SY, Lin RY, Liu IL. Folliculotropic mycosis fungoides successfully treated with bath psoralen plus ultraviolet a therapy.Dermatol Sin 2022;40:192-193

How to cite this URL:
Hung YT, Lee MS, Huang TC, Wen SY, Lin RY, Liu IL. Folliculotropic mycosis fungoides successfully treated with bath psoralen plus ultraviolet a therapy. Dermatol Sin [serial online] 2022 [cited 2023 Jan 30 ];40:192-193
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Full Text

Dear Editor,

A 71-year-old Asian, female patient presented with numerous asymptomatic skin lesions on the trunk and limbs for years. She denied any symptoms of systemic disease. On physical examination, numerous discrete flesh-colored to light brown 2–3 mm follicular papules were located symmetrically on the neck, trunk, and all four extremities. Some papules resembled comedones. An 8 mm × 6 mm nonscaly, erythematous plaque with follicular prominence on the right upper eyelid was also present. On dermoscopy, follicular papules showed brown- or white-colored clods with a brown halo surrounding the follicles [Figure 1].{Figure 1}

An incisional biopsy of a chest lesion revealed moderate lymphocytic folliculotropic and perifollicular infiltration with follicular mucinosis. Immunohistochemically, most of the infiltrated lymphoid cells were CD3+ T cells with prominent folliculotropism, although interfollicular areas of epidermis were spared from infiltration. Most of T cells were CD4+, and as a result, there was significantly increased CD4+-to-CD8+ ratio (>10:1). An incisional biopsy was also performed on the infiltrative plaque on the right upper eyelid, which demonstrated a similar pathologic pattern. Further, Pautrier's microabscesses were present in the intrafollicular epithelium with atypical CD4+ T cells with the loss of CD7 expression [Figure 2]. Laboratory tests revealed a slight elevation of lactic dehydrogenase (278 U/L). Whole-body computed tomography (CT) demonstrated no evidence of visceral involvement, and peripheral blood smear did not reveal the presence of atypical cells. T cell receptor gene rearrangement analysis of lesional skin revealed γ gene monoclonality. Given this evidence, the diagnosis of folliculotropic mycosis fungoides (FMF) was established. After diagnosis, the patient initially received narrow-band ultraviolet B (nbUVB) phototherapy and topical corticosteroids, due to concern of side effects caused by psoralen plus ultraviolet A (PUVA). However, the outcome was unsatisfactory. The patient subsequently started bath PUVA therapy with methoxsalen later. Since FMF involves deeper part of the skin, higher concentration of methoxsalen (100 mg/L) was applied on the lesional skin for 10 min. The patient then soaked into 80 L of water (0.25 mg/L) for 30 min to obtain uniform distribution. After total 622 J/cm2 cumulative UVA dose, nearly complete clearing of lesions was observed on both clinical and histopathological follow-up [Figure 1] and [Figure 2].{Figure 2}

FMF is a rare, relatively aggressive variant of cutaneous T cell lymphoma. Common manifestations of early FMF are keratosis pilaris-/keratosis spinulosa-like lesions and acneiform lesions with or without alopecia. Advanced-stage patients present with infiltrated or indurated plaques or tumors. Recent studies revealed involvement of the head and neck in all tumor-stage cases, whereas early-stage lesions involved mainly the trunk and limbs.[1] The diagnosis of FMF is mainly confirmed by skin biopsy. Histologically, FMF is characterized by atypical T lymphocytes that preferentially infiltrate the follicular epithelium and spare interfollicular epidermis. Immunohistologically, the CD4+-to-CD8+ T cell ratio is frequently greater than or equal to 10:1.[2] Loss of one or more pan-T cell markers, especially CD7, can be indicative of a neoplastic process.[3]

Treatment strategies for FMF generally follow those for tumor-stage MF. Follicular involvement is better treated with PUVA than nbUVB due to deeper penetration of UVA into the mid- or lower dermis. A higher number of PUVA sessions and a higher cumulative dose were required to achieve a complete response in patients with early FMF compared to those with early classic MF.[4]

Although systemic PUVA achieves a favorable clinical response in patients with many inflammatory and malignant conditions, bath PUVA had been developed as an attractive alternative treatment owing to lower risk of gastrointestinal side effects and less possible phototoxic hazards to the eyes. Several publications have reviewed the efficacy of bath PUVA as a monotherapy or combination therapy, but few emphasized the folliculotropic variant. Pavlotsky et al. studied bath PUVA as a therapeutic modality and reported a complete response rate of 71% in FMF.[5] One study revealed that the photoimmunologic effects of bath PUVA include decreasing CCR4(+) cells and regulatory T cells in MF lesions.[6] In another study, topical psoralen achieved a higher epidermal concentration than delivery via the oral route, especially at the end of the application period.[7] Therefore, we concluded that the intrafollicular accumulation of topical psoralen and the superficial location of pathology in our patient contributed to the favorable response.

This case presentation suggests that for elderly patients presenting with atypical keratosis pilaris-like lesions, a skin biopsy is warranted to rule out follicular lymphoproliferative disorders. In FMF patients, PUVA phototherapy results in more favorable clinical outcomes than nbUVB. Further, bath PUVA can be considered as a treatment modality in patients with superficial lesions who cannot tolerate oral PUVA.

Declaration of patient consent

The authors certify that they have obtained appropriate patient consent form. In the form, the patient has given her consent for the images and other clinical information to be reported in the journal. The patient understands that her name and initial will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

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1Hodak E, Amitay-Laish I, Atzmony L, Prag-Naveh H, Yanichkin N, Barzilai A, et al. New insights into folliculotropic mycosis fungoides (FMF): A single-center experience. J Am Acad Dermatol 2016;75:347-55.
2Gerami P, Guitart J. The spectrum of histopathologic and immunohistochemical findings in folliculotropic mycosis fungoides. Am J Surg Pathol 2007;31:1430-8.
3Harvey NT, Spagnolo DV, Wood BA. 'Could it be mycosis fungoides?': An approach to diagnosing patch stage mycosis fungoides. J Hematopathol 2015;8:209-23.
4Amitay-Laish I, Prag-Naveh H, Dalal A, Pavlovsky L, Feinmesser M, Hodak E. Treatment of early folliculotropic mycosis fungoides with special focus on psoralen plus ultraviolet A. Acta Derm Venereol 2018;98:951-5.
5Pavlotsky F, Hodak E, Ben Amitay D, Barzilai A. Role of bath psoralen plus ultraviolet A in early-stage mycosis fungoides. J Am Acad Dermatol 2014;71:536-41.
6Kato H, Saito C, Ito E, Furuhashi T, Nishida E, Ishida T, et al. Bath-PUVA therapy decreases infiltrating CCR4-expressing tumor cells and regulatory T cells in patients with mycosis fungoides. Clin Lymphoma Myeloma Leuk 2013;13:273-80.
7Grundmann-Kollmann M, Podda M, Bräutigam L, Hardt-Weinelt K, Ludwig RJ, Geisslinger G, et al. Spatial distribution of 8-methoxypsoralen penetration into human skin after systemic or topical administration. Br J Clin Pharmacol 2002;54:535-9.