ANGIOIMMUNOBLASTIC LYMPHOMA (AILD-TYPE T-CELL LYMPHOMA) WITH HYPERPLASTIC GERMINAL-CENTERS

Angioimmunoblastic T-cell lymphoma (or angioimmunoblastic lymphadenopa thy with dysgammaglobulinemia [AILD]) was originally considered to be an abnormal immune reaction in which reactive follicles with germinal centers (GCs) an usually absent. When hyperplastic GCs are present alo ng with an angioimmunoblastic reaction, the lesion has been interprete d as a benign hyperimmune reaction. We report seven patients with angi oimmunoblastic T-cell lymphoma (AITL) who initially had hyperplastic G Cs, shown to be malignant lymphoma by further studies and clinical fol low-up. Clonal T-cell populations were observed in all specimens evalu ated, and sequential biopsies showed histologic progression to typical AITL in two patients. Clinical presentation was characterized by gene ralized lymphadenopathy of acute onset, constitutional symptoms, hepat osplenomegaly, skin rash, and polyclonal hypergammaglobulinemia in fiv e patients; regional adenopathy preceded generalized adenopathy in two patients. Five patients had rapid progression of disease, and three p atients whose treatment was delayed due to inadequate evidence to diag nose lymphoma died of infection. The initial biopsy findings of each p atient were similar and showed angioimmunoblastic proliferation, hyper plastic GCs with ill-defined borders, and interfollicular tingible-bod y macrophages. These GCs differed from occasional residual follicles o f typical AITL in that the GCs were enlarged and hyperplasia of follic ular dendritic cells was not seen. Diagnostic clear cells were not obs erved. Apoptotic bodies were markedly increased and bcl-2(+) lymphocyt es were sparse compared with typical AITL. Results of in situ hybridiz ation for Epstein-Barr virus were positive in each case. We conclude t hat hyperplastic germinal centers with ill-defined borders and frequen t interfollicular tingible-body macrophages occur in a histologic vari ant of AITL that is necessary to recognize for early diagnosis and tre atment.