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Case Reports

Abstract

A 53-year-old woman with longstanding systemic lupus erythematosus and a kidney transplant (1999) presented with multiple asymptomatic red-brown papules and soft nodules on the forearms, lateral thighs, and upper back. Some lesions showed overlying skin wrinkling and dimpling on palpation, suggestive of anetoderma. The patient first noted the lesions two years earlier. An initial biopsy at another institution demonstrated interstitial granulomatous dermatitis with plasma cells. Repeat biopsies revealed nodular dermal infiltrates of mature lymphocytes and plasma cells with kappa light chain restriction, scattered interstitial granulomas, and marked reduction of dermal elastic fibers on Verhoeff–Van Gieson stain. EBV in situ hybridization highlighted numerous positive cells. PCR for the immunoglobulin heavy chain gene confirmed a clonal B-cell population. The findings were consistent with EBV-positive cutaneous marginal zone lymphoma, a rare form of post-transplant lymphoproliferative disorder (PTLD). Bone marrow biopsy showed no evidence of lymphoid neoplasm, and CT chest and PET/CT did not show signs of systemic lymphoma. Immunofixation electrophoresis and serum free light chain assay were unrevealing of a plasma cell dyscrasia or monoclonal gammopathy. The patient is currently receiving four weekly doses of rituximab. PTLD comprises a heterogeneous spectrum of predominantly extranodal B-cell proliferations with variable clinical presentations. This case illustrates a rare cutaneous variant associated with EBV and emphasizes the diagnostic value of repeat biopsies with comprehensive immunohistochemical and molecular studies in post-transplant patients with persistent or atypical skin lesions.