Cutaneous involvement in prelymphomatous angioimmunoblastic lymphadenopathy.

We describe prelymphomatous angioimmunoblastic lymphadenopathy with cutaneous involvement in a 73-year-old female patient. A maculopapular skin eruption was the first sign of the disease. Skin histology showed extensive perivascular and periadnexal mixed lymphoid infiltrates including centroblasts and immunoblasts with a high proliferative index and with focal erythrocyte extravasation. Lymph node histology confirmed the diagnosis, showing nearly complete effacement of the follicular architecture, a mixed lymphoid infiltrate, and numberous high endothelial venules in an expanded T-cell zone. Immunohistochemistry, however, demonstrated preservation of at least some follicular structures. T-cell receptor gene rearrangement analysis revealed oligoclonal patterns in both lymph node and skin specimens. In contrast, immunoglobulin heavy-chain gene rearrangement analysis revealed a polyclonal pattern. Accordingly, the disease was classified as a prelymphomatous stage of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) with specific involvement of both lymph node and skin. The patient was treated with high-dose corticosteroids, and long-lasting remission was induced. In contrast to our case, most reported cases of AILD show a monoclonal T-cell pattern indicating AILD-type lymphoma. Therefore we discuss the concept of prelymphomatous AILD developing into AILD-type lymphoma. Persistence of some antigenic stimulus may induce the proliferation of a monoclonal population of lymphoid cells from a polyclonal background in a multistep fashion. Proper treatment of AILD at an early, prelymphomatous stage may protract or inhibit development of full-blown, fatal AILD-type lymphoma.