Cutaneous pseudolymphomas are often difficult to distinguish from malignant lymphomas. We report a case of cutaneous pseudolymphoma arising as Wolf’s isotopic response following herpes simplex virus (HSV) infection and highlight the importance of clinical history in making this diagnosis.
A man in his 70s presented with a persistent eruption of 5 years’ duration. He had been treated with oral methotrexate for presumed chronic dermatitis after treatments with oral antibiotics, oral doxepin, and UV-B phototherapy had failed. Physical examination was notable for multiple erythematous and violaceous plaques and nodules clustered on the superior buttocks and intergluteal cleft bilaterally (Figure 1). Syphilis screen results were negative. Skin biopsy revealed a dense infiltrate of atypical CD4+ small to medium-sized lymphocytes in the upper dermis admixed with eosinophils and plasma cells (Figure 2A). Epidermotropism was not identified. Molecular analysis of the T-cell receptor gamma gene showed a weak clonal band in a polyclonal background. A diagnosis of atypical T-cell infiltrate, suggesting but not diagnostic for mycosis fungoides, was made. The patient was instructed to continue taking oral methotrexate in combination with topical clobetasol and to follow up every 3 months.