LAUSR

Chronic graft-versus-host-disease (cGVHD) is a frequent and severe complication of allogeneic hematopoietic stem cell transplantation (AHSCT). According to the National Institutes of Health, diagnostic clinical features of cGVHD include poikiloderma, lichen planus-like eruption, deep sclerotic features, morphea-like superficial sclerotic features and lichen sclerosus-like lesions [1]. Lichen planus pigmentosus (LPP) is an uncommon variant of lichen planus, mainly described in India and the Middle East. This cosmetically distressing pigmentary disorder is characterised by large hyperpigmented patches in sun-exposed areas or in the folds. Histological features of LPP include vacuolar degeneration of the basal cell layer and pigment incontinence in the dermis [2, 3]. Therapeutic options of LPP include topical corticosteroids, topical tacrolimus, depigmenting creams, isotretinoin and dapsone [4, 5]. Several types of lichenoid dermatitis have been described in skin cGVHD namely lichen planus, bullous lichen and lichen sclerosus and atrophicus [1, 4, 5]. We describe a new type of lichenoid skin cGVHD mimicking LPP. We performed a retrospective monocentric study (Saint Louis Hospital, Paris, France) on 11 patients with LPP lesions seen at a dedicated dermatological post-transplant consultation between 2011 and 2016. Inclusion criteria for LPP were clinical +/− histological signs of LPP appearing after AHSCT and other definite symptoms of cGVHD (according to NIH criteria [6]) involving the skin or other organs. Clinical features and response to topical and systemic treatments were recorded retrospectively. Clinical pictures were performed routinely after informed consent of the patient. The response of LPP to treatments was assessed by the physician and classified as « complete response », « partial response », « stability» or « worsening » [7–9]. Main characteristics of the 11 LPP patients are summarised in Supplemental Table 1. Nine patients had extracutaneous cGVHD: GI tract n= 2; liver n= 4; bronchiolitis obliterans n= 3; opthalmologic n= 6; muscular involvement n= 1 and articular involvement n= 1. Seven patients had classical cGVHD skin symptoms: lichen planus n= 4, morphea n= 3, deep sclerotic features n= 1 and poikiloderma n= 3. Associated lichen planus was often present: oral (eight patients), genital (three patients) and ungueal lesions (one patient). Median time from AHSCT to LPP onset was 8 months (range 3–22). Patients presented with dark brown or slate grey patches or papules preferentially on sun-exposed areas (see examples in Fig. 1). There was no previous 'inflammatory' skin stage, as opposed to the red/ violaceous lesions that are typically seen in lichen planus. A skin biopsy was performed in five cases showing lichenoid histological features (basal layer vacuolisation and Gérard Socié and Jean-David Bouaziz contributed equally to this work.