Chronic, actinic dermatitis simulating a follicular, large, cleaved B-cell lymphoma

We report a 31-year-old male with a history of chronic photosensitivity since childhood. Systemic beta-carotene and systemic corticosteroids had improved his condition in the past. Examination revealed red, scaly plaques with yellow crusts present on sun-exposed skin. A skin biopsy from one of these plaques revealed dermal lymphoid nodules sparing the epidermis. The cells in the center of the lymphoid follicles were CD20 and CD22 positive (CD30 negative). There was no kappa or lambda light-chain restriction. The follicles were surrounded by a mantle of small lymphocytes composed of T-helper and T-suppressor cells. A diagnosis of malignant B-cell lymphoma of the follicular, large cleaved cell type was suspected. Further laboratory and radiologic evaluations were unremarkable. Molecular genetics studies from a skin biopsy detected a clonal immunoglobulin gene rearrangement by polymerase chain reaction. Phototesting revealed a minimal erythema dose (MED) for UVB and UVA of 5 mJ/cm 2 and 5 J/cm 2 , respectively. Typical clinical lesions were reproduced with UVB at 20 mJ/cm 2 . The patient improved with systemic corticosteroids and hydroxychloroquin. To our knowledge, this is the first report in the literature of chronic actinic dermatitis simulating a cutaneous B-cell lymphoma. This histologic variation should be kept in mind in patients with chronic actinic dermatitis.