Understanding the enigmatic association between mycosis fungoides and psoriasis: Report of two cases and review of the literature

Cutaneous T-cell lymphoma: Consensus on diagnosis and management in Taiwan

Cutaneous T cell lymphomas (CTCLs), with mycosis fungoides (MF) and Sézary syndrome (SS) as the classic types, are the commonest group of primary cutaneous lymphomas. The diverse clinical manifestation and non-specific histologic findings of early lesions in CTCLs render diagnosis challenging. Treatment modalities also vary and include topical and oral medications, chemotherapy, phototherapy, and radiation therapies. Local dermatological, hemato-oncologic and radiotherapeutical experts in Taiwan convened meetings in 2023 to review and discuss the latest evidence and updates regarding diagnosis and management of CTCLs. A consensus was developed with the aim to raise awareness and understanding, provide practical guidance for early diagnosis and appropriate management, and ultimately optimize care to maximize benefits of patients.

When mycosis fungoides seems not to be within the spectrum of clinical and histopathological differential diagnoses

The most prevalent primary cutaneous T-cell lymphoma, mycosis fungoides (MF), is characterized by the development of plaques and nodules after an erythematous patchy phase that is non-specific. An infiltrate of atypical small- to medium-sized cerebriform lymphocytes in the superficial dermis, with variable epidermotropism, is the histopathological hallmark of the disease. In more advanced stages of the illness, large-cell transformation may be seen. Early diagnosis of MF can be very challenging based only on histopathologic or clinical findings, so it is critical to have a clinical-pathological correlation. Many atypical variants of MF that deviate from the classic Alibert-Bazin presentation of the disease have been described over the past 30 years, sometimes with different prognostic and therapeutic implications. Clinically or histopathologically, they can mimic a wide range of benign inflammatory skin disorders. To make a conclusive diagnosis in these cases, it is recommended to take multiple biopsies from various lesions and to carefully correlate the clinical and pathological findings. We have outlined the various facets of the illness in this review, positioning MF as a "great imitator", with an emphasis on the more recently identified variations, differential diagnosis, and its benign mimics.

Increased Risk of Cutaneous T-Cell Lymphoma Development after Dupilumab Use for Atopic Dermatitis

There have been several reports of dupilumab use and the development of CTCL; however, the risk of CTCL development has not been adequately evaluated at the population level. The objective of this study is to determine whether dupilumab administration for AD is associated with an increased risk of developing CTCL and to identify at-risk populations within this group. This retrospective cohort study used TriNetX, a deidentified medical record database including over 107 million patients, to identify eligible patients. Treatment and control groups were evaluated for the development of CTCL. Patients of any age with a documented diagnosis of AD were included. The treatment cohort included individuals treated with dupilumab, while the control cohort included AD patients treated with alternative therapies. Selected biologics were excluded from both groups. Subgroup analyses were performed to evaluate three age groups and to identify whether the risk of CTCL development was higher within a given time frame after starting dupilumab. We identified a total of 1,181,533 patients with AD. Of these, 19,612 patients were prescribed dupilumab. Both treatment and control groups included 19,612 patients matched for age, race, and sex. The mean age was 32.3 years (P = 0.96), and females accounted for approximately 52% (P = 0.93) in both groups. Patients treated with dupilumab for AD had an increased relative risk (RR) of developing CTCL compared to those never treated with dupilumab (RR = 4.59, 95% confidence interval 2.459-8.567, P < 0.0001). Subgroup analysis revealed that about half of the CTCL cases after dupilumab therapy (54.5%, 30/55) occurred in patients over the age of 60 years. In contrast, all CTCL cases (100%, 12/12) within the untreated cohort were observed in individuals over the age of 60. Of the patients diagnosed with CTCL following dupilumab use, the majority (62%, 34/55) were diagnosed within the first year. Overall, we find that the use of dupilumab for treating AD is associated with an increased relative risk of developing CTCL. This risk is highest in the first year of therapy and in adult patients. These findings suggest exercising caution in treating select groups of patients with dupilumab.

Risk of Cutaneous T Cell Lymphoma with Psoriasis Biologic Therapies

BACKGROUND

The risk of developing cutaneous T cell lymphoma (CTCL) in patients using psoriasis biologics has not been well characterized. The goals of this review were to investigate the incidence of CTCL in patients with psoriasis receiving biologic therapy in clinical trials and psoriasis registries, and to review cases of CTCL and biologic use reported in scientific publications.

METHODS

The US National Library of Medicine clinical trials database (clinicaltrials.gov) was queried to identify phase 3 and 4 clinical trials of the 12 biologic agents currently FDA approved for psoriatic disease. The incidence of CTCL in these trials was examined and summarized. To examine the incidence of CTCL in psoriasis registries, a Medline search was conducted. Finally, we performed a systematic review of CTCL cases reported in the literature.

RESULTS

Only two cases of CTCL were reported in 35,801 subjects with psoriasis receiving a biologic agent in the active arm of 108 psoriasis phase 3 clinical trials. One of these CTCL cases was determined by the investigator to be CTCL misdiagnosed as psoriasis prior to randomization. No cases of CTCL were reported in 5440 subjects with psoriasis in 34 phase 4 clinical trials. Only one case of CTCL was identified in 34,111 registry subjects. In the literature, tumor necrosis factor (TNF) inhibitors had the highest number of reported cases of CTCL (34 cases), followed by interleukin (IL)-17 inhibitors (7 cases), and IL-12/23 inhibitors (6 cases). No cases of CTCL were found to be reported with IL-23 inhibitors.

CONCLUSION

Our findings indicate that the development of CTCL is rare in the setting of psoriasis biologic use. Of the limited number of cases of CTCL found, most were in the setting of TNF inhibitor use and no cases of CTCL were reported in the setting of IL-23 inhibitor use.

Mycosis fungoides with Psoriasiform plaques: A case report and review of the literature

Mycosis fungoides (MF) is the most common variant of primary skin T-cell lymphoma. It typically manifests as an indolent progressing cutaneous eruption with erythematous scaly patches or plaques. Due to the nonspecific pathological findings, it can be easily misdiagnosed as psoriasis. A 34-year-old woman with a history of psoriasiform plaques for 12 years was referred to our dermatology clinic. In the beginning, the diagnosis of psoriasis was made and topical steroids were prescribed: it did not exhibit any clinical improvement. During the visit, skin biopsy was performed and the diagnosis of MF was confirmed. Treatment with PUVA, prednisolon, methotrexate, topical ointment including ucerin, urea, and clobetasol were initiated. Significant improvement in all lesions were observed after 1 month of the treatment, and within a year, the disease improved dramatically after PUVA therapy. In refractory cases of psoriasiform plaques that are progressive and/or ulcerative despite the optimal treatment, biopsy is required and a possible diagnosis of MF should be kept in mind.

Phototherapy combined with systemic agents for mycosis fungoides

The choice of tactics for managing a patient with mycosis fungoides is determined by the stage of the disease. In the early stages of mycosis fungoides, a treatment approach using external therapy and various ultraviolet irradiation spectra (UVB-311 nm and PUVA therapy) is preferable. With insufficient efficiency and / or short remissions in some patients, it is possible to use combined methods in the early stages: PUVA therapy or UVB-311 nm therapy. in combination with systemic therapy, including interferon (IFN) 2b preparations, methotrexate and retinoids. The results of original studies demonstrate an increase in the overall response rate when combining PUVA therapy with IFN- or retinoids in patients with stages IB-IIB. The effectiveness of combined treatment regimens using UVB-311 nm remains insufficiently studied.