DP26: Predominantly photosensitive CD30⁺ lymphoproliferative dermatosis

Leah Mapara, Faris Kubba, Eva Tsele and Fernanda Teixeira

London North West University Healthcare NHS Trust, Harrow, UK

A 63-year-old man presented with a 5-year history of a mildly pruritic skin rash, which was aggravated by sun exposure. This had been spreading gradually. His past medical history included hypertension, type 2 diabetes, asthma and ischaemic heart disease. He has no previous history of skin rashes. He was recently started on clopidogrel, ivabradine, prednisolone and lansoprazole for recent coronary artery bypass grafting and asthma exacerbation. On examination, he had a combination of erythematous and purple papules on his forehead and nose, as well as on the dorsum of hands, with truncal and proximity extremities spared. There was no evidence of lymphadenopathy. Our initial differential diagnosis included actinic prurigo, actinic reticuloid, lymphomatoid papulosis or a photosensitive drug reaction. Patch testing was positive for nickel, paraphenylenediamine, methylchloroisotheozolinone and methylisothiazinoline, parabens and colofoneum. Punch biopsies from the nose were suggestive of lymphomatoid papulosis showing dermal lymphoid infiltrate composed of small and medium-sized lymphoid cells with spongiosis. Parakeratosis was noted with mild epidermal basal atypia suggestive of actinic keratosis. Immunohistochemistry revealed T-cell markers and a number of CD30⁺ medium-sized cells. Activin A receptor like kinase 1, epithelial membrane antigen and CD56 were negative in the lymphocytes. There was no atypia seen. On further clinical correlation, this appeared to be more in keeping with an inflammatory dermatosis given that the clinical course subsided with protection from direct sun exposure, which favoured a diagnosis of a photosensitive pseudolymphoma. He was subsequently referred to a specialist photodermatology centre for photopatch testing and diagnosed with actinic reticuloid. It was recommended that he avoid sun exposure and use sun protection factor 50 sunscreen and topical steroids. Over time, his skin improved significantly. It is important to recognize actinic retinoid as a sunlight-induced pseudolymphoma, which presents on sun-exposed areas of the skin. These noncancerous lymphocytic skin disorders may mimic malignant lymphoma but usually subside on sun avoidance. Histological analysis, as seen in this case, can resemble lymphoma with presence of activated T cells, macrophages and B cells. Treatment consists of significant changes to the patient’s lifestyle and avoidance of any contact allergens, including sun exposure (Lugović-Mihić L, Duvancić T, Situm M et al. Actinic reticuloid—photosensitivity or pseudolymphoma?—A review. Coll Antropol 2011; 35(Suppl. 2): 325–9).