Histiocytic necrotizing lymphadenitis, or Kikuchi's lymphadenitis (KL), is an unusual form of lymphadenitis, generally with self-limited clinical course. KL has been reported in rare patients infected with the human immunodeficiency virus (HIV). Pathogenesis of the lesion is probably related to an impaired immune function. The purpose of the present article is to report on one case in which KL was diagnosed in an HIV-infected patient. Histomorphology and immunophenotype were similar to previous reports, but a focus of activated CD30+ macrophages was seen, what might be due to the immunological status of the patient. EBV was not detected on the sections using the in situ hybridization technique. Although rare, the occurrence of KL in HIV-infected subjects must be emphasized, because of the potential misdiagnosis of malignancy, especially in the presence of CD30+ cells.445265268Abad, A., Baraia-Etxaburu, J., Muñoz, J., Santamaria, J.M., Kikuchi disease in an acquired immunodeficiency syndrome patient (1999) Enferm. Infec. Microbiol. Clin., 17, pp. 193-194Aguiar, J.I., Paniago, A.M., Aguiar, E.S., Kikuchi's disease: Report of 2 cases and a brief review of the literature (2000) Braz. J. Infect. Dis., 4, pp. 208-211Andreesen, R., Brugger, W., Löhr, G.W., Bross, K.J., Human macrophages can express the Hodgkin's cell-associated antigen Ki-1 (CD30) (1989) Amer. J. Path., 134, pp. 187-192Bataille, V., Harland, C.C., Behrens, J., Cook, M.G., Holden, C.A., Kikuchi disease (histiocytic necrotizing lymphadenitis) in association with HTLV1 (1997) Brit. J. Derm., 136, pp. 610-612Berti, F., De Rosa, L., Sorrentino, R., The immunological aspects of Kikuchi's disease. A clinical case report (1994) Recenti Progr. Med., 85, pp. 113-116Chang, K.L., Arber, D.A., Weiss, L.M., CD30: A review (1993) Appl. Immunohistochemistry, 1, pp. 244-255Cossu, A., Lissia, A., Cossu, S., Malattia di Kikuchi e linfoadenopatia proteinacea in quattro pazienti con infezione da HIV (1998) Pathologica, 90, pp. 20-26Dorfman, R.F., Berry, G.J., Kikuchi's histiocytic necrotizing lymphadenitis: An analysis of 108 cases with emphasis on differential diagnosis (1988) Semin. Diagn. Path., 5, pp. 329-345Ereno, C., Kikuchi lymphadenitis and AIDS (1999) Histopathology, 34, p. 273Felgar, R.E., Furth, E.E., Wasik, M.A., Gluckman, S.J., Salhany, K.E., Histiocytic necrotizing lymphadenitis (Kikuchi's disease): In situ end-labeling, immunohistochemical, and serologic evidence supporting cytotoxic lymphocyte-mediated apoptotic cell death (1997) Mod. Path., 10, pp. 231-241Kuo, T.T., Kikuchi's disease (histiocytic necrotizing lymphadenitis). A clinicopathologic study of 79 cases with an analysis of histologic subtypes, immunohistology and DNA ploidy (1995) Amer. J. Surg. Path., 19, pp. 798-809Llatjos, M., Romeu, J., Clotet, B., A distinctive cytologic pattern for diagnosing tuberculous lymphadenitis in AIDS (1993) J. Acquir. Immune Defic. Syndr., 6, pp. 1335-1338Lorand-Metze, I., Vassallo, J., Mori, S., Histiocytic necrotizing lymphadenitis in brazil: Report of a case and review of the literature (1994) Path. Int., 44, pp. 548-550Martinez-Vazquez, C., Potel, C., Angulo, M., Nosocomial Kikuchi's disease - A search for herpesvirus sequences in lymph node tissues using PCR (2001) Infection, 29, pp. 143-147Menasce, L.P., Banerjee, S.S., Edmondson, D., Harris, M., Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease): Continuing diagnostic difficulties (1998) Histopathology, 33, pp. 248-254Pasquinucci, S., Donisi, P.M., Cavinato, F., Belussi, F., Kikuchi's disease in a patient infected with AIDS (1991) AIDS, 5, p. 235Pileri, S., Kikuchi, M., Helbron, D., Lennert, K., Histiocytic necrotizing lymphadenitis without granulocytic infiltration (1982) Virchows Arch. Abt. A., 395, pp. 257-271Pileri, A.S., Sabattini, E., Costigliola, P., Kikuchi's lymphadenitis and HIV infection (1991) AIDS, 5, pp. 459-461Spies, J., Foucar, K., Thompson, C.T., LeBoit, P.E., The histopathology of cutaneous lesions of Kikuchi's disease (necrotizing lymphadenitis): A report of 5 cases (1999) Amer. J. Surg. Path., 23, pp. 1040-1047Yufu, Y., Matsumoto, M., Miyamura, T., Parvovirus B19-associated haemophagocytic syndrome with lymphadenopathy resembling histiocytic necrotizing lymphadenitis (Kikuchi's disease) (1997) Brit. J. Haemat., 96, pp. 868-871