A rare case of early‐onset lymphomatoid papulosis refractory to brentuximab vedotin

Abstract

Dear Editor Lymphomatoid papulosis (LyP) is a non-aggressive CD30+ primary cutaneous T cell lymphoma characterized by a recurrent, spontaneously regressive papulonodular eruption. Despite his malignant histologic features, LyP has a good prognosis, with a 10-year survival rate close to 100%. LyP can occur at any age, but in children is very exceptional and, because of its rarity, it has not yet beenwell described. We present a case of a 32-year-old male patient affected by LyP during the last 22 years. He was referred to our clinic at the age of 10 years old for the presence of a recurrent and self-remittent eruption characterized by erythematous papular lesions on the lower limbs and genitalia since he was 2 years old. The eruption was mildly itchy and partially responsive to topic steroids. The incisional biopsy performed revealed a classic type A LyP, with presence of dense dermal inflammatory infiltrate, consisting in neutrophils, eosinophils and atypical CD30+ T cells. The patient was initially treated with cycles of topic mometasone furoate and with a “wait-and-see strategy” of periodic follow-up. Over a period of 15 years, only a few disease flares occurred, which were successfully controlled with topical steroids. At the age of 25 years old, due to a worrisome exacerbation, manifesting as a generalized reddish-violaceous papules and nodules on the trunk and on the lower limbs, a second biopsy was executed. The histological findings were morphologically and immunophenotypically similar to the first histological evaluation. Immunohistochemistry showed expression of CD30 and CD25, MIB1 (+60%), CD2, CD4 and TiA1 (Figure S1). A positron emission tomography-computed tomography (PET-CT) did not show extracutaneous localization. Thus, methotrexate (MTX) 10 mg/week was started, with a progressive improvement of the clinical conditions. Nevertheless, 6 months later, another disease relapse occurred, presenting as violaceus papules and nodules on the trunk (Figure 1A) and lower limbs (Figure 1B). Furthermore, the patient showed a bulky nodule on the left ankle and axillary, inguinal and cervical lymphadenopathies. The third biopsy was performed on the bulky nodule of the ankle and the histologic findings revealed anaplasia with high proliferative index (>90%) associated with features of LyP type A. The blastic elements were positive for CD30, CD45, CD43 andMUM1. Moreover, PET-CT evidenced metabolic progression of disease on lymph nodes and skin, but a bonemarrow biopsy excluded a systemic involvement. Considering the refractoriness to the classic therapies, intravenous infusions with the chimeric monoclonal antibody anti-CD30 brentuximab vedotin (1.8 mg/kg every 20 days) were started. The patient showed an initial improvement, consisting in decrease of number and size of cutaneous lesions and in remission of lymphadenopathies, with no adverse effects related to the therapy.