Elephantiasis verrucous lesions on psoriatic plaque improved with anti-IL-23p19 antibody therapy

Psoriasis is an autoimmune disease characterized by the repetitive proliferation of keratinocytes. Immunological and genetic studies have identified interleukin (IL)-17 and IL-23p19 as key cytokines in the pathogenesis of psoriasis.1 Immune targeting of these cytokines as well as tumor necrosis factor (TNF)-α, through the use of biological therapies, has revolutionized the management of severe chronic plaque psoriasis. Elephantiasis nostras verrucosa (ENV) usually occurs in the lower extremities and is typically characterized by gross enlargement of the affected region with a verrucous, papillomatous, cobblestone-like appearance. The mechanism is unknown, but ENV is thought to be related to chronic lymphoedema. Secondary lymphoedema has many causes, including obesity, infectious etiologies, trauma, surgery, and radiation.2 Histopathological findings of ENV are pseudoepitheliomatous hyperplasia, dermal fibrosis, and dilated lymphatic vessels.3 In this report, we present a case of ENV on psoriasis, both conditions successfully treated with the use of biologics. A 61-year-old man having a 30-year history of psoriasis vulgaris, treated with topical steroids, presented with well-demarcated, erythematous, raised plaques, and a white micaceous scale on the back, shoulders, and extremities. His medical history included chronic kidney disease and stable Hodgkin lymphoma. Additionally, he had lymphoedema with indentations on the right lower limb resulting from a groin lymph node biopsy performed for Hodgkin lymphoma. The patient presented to our hospital with a 2-year history of expanding verrucous lesions on the anterior aspect of his right lower limb, which developed over pre-existing psoriatic erythematous lesions (Figure 1a). The verrucous lesions had previously been treated with salicylic acid ointment, vitamin D3 compound, and UVB phototherapy, all of which yielded unsuccessful results. A skin biopsy of the verruca revealed papillomatosis, hyperkeratosis, edema of dermis, and dilated lymphatic vessels, consistent with ENV (Figure 1b,c). Munro microabscesses, parakeratosis, and absence of the granular layer, which are characteristics of psoriasis vulgaris, were also noted (Figure 1d,e). Human papillomavirus was not detected. We treated his psoriasis vulgaris with an anti-IL-23p19 antibody, risankizumab. Following three courses of risankizumab, the psoriatic lesions began to regress; complete disappearance was observed after the fourth administration. Notably, in addition to significant improvement in his psoriasis vulgaris, treatment with risankizumab also resulted in the resolution of the ENV (Figure 1f). Lymphoscintigraphy revealed the presence of radiotracer uptake in the dermal lymphatics, indicating dermal backflow in the right lower limb. It means lymphedema and lymphostasis due to lymph node resection. Remodeling of the lymphatic vascular system may occur in psoriasis.4 In addition, basal inflammation and cytokine production, including fibroblast growth factor in psoriasis lesions, may contribute to the progression of epidermal hyperplasia and dermal fibrosis of ENV. In this case, we speculated that ENV was caused by long-term inflammation of psoriasis and lymphedema due to a groin lymph node biopsy. Treatment for psoriasis vulgaris can potentially reduce local inflammation and may have led to ENV improvement. None. The authors did not receive any financial support for the present case. CONFLICT OF INTEREST STATEMENT Keiichi Yamanaka is an Editorial Board member of Journal of Dermatology and a co-author of this article. To minimize bias, he was excluded from all editorial decision-making related to the acceptance of this article for publication. The research was conducted in accordance with the Declaration of Helsinki. The patient gave consent for his photographs and medical information to be published in print and online with the understanding that this information is publicly available. The paper is exempt from ethical committee approval, because of the single case study.