Syphilitic lymphadenopathy. Histology and human immunodeficiency virus status

Few reports on syphilitic lymphadenopathy have appeared in 20 years, and none have compared findings in patients with and without human immunodeficiency virus (HIV) infection, despite the recent epidemic spread of syphilis and HIV. Twelve cases of syphilitic lymphadenopathy were studied and grouped according to HIV status. Patients were 21 to 62 years old (median, 29 years); 7 were men, 5 were women. Biopsy sites were cervical (7 cases), inguinal (4), and axillary (1) lymph nodes. All patients had evidence of syphilis. Rapid plasma reagin titers ranged from 1:32 to 1:512. Treponemal hemagglutination was positive in all cases tested. Spirochetes were found with Steiner staining in 2 cases. HIV testing was positive in 4, negative in 2, and unknown in 6 cases. Lymph nodes were enlarged and often fragmented due to capsular fibrosis and chronic inflammation, with focal obliteration of the subcapsular sinus. Follicular and interfollicular hyperplasia was seen in all cases and was usually marked, with prominent vascular proliferation, plasma cells, immuno-blasts, histiocytes, and occasional neutrophils. Follicle lysis and granulomas suggestive of unconfirmed toxoplasmosis were each seen in 1 case, and Kaposi sarcoma in 2, all in HIV-positive patients. Lymphoplasmacytic infiltration was marked, especially in interfollicular areas, with peri-vascular plasma cell cuffing in all cases and obliterative endarteritis in about half (7 of 12, 56%). Immunostaining for CD45RO (UCHL-1), CD20 (L26), kappa, lambda, and CD68 (Kp-1) revealed a mixed population of T cells, polyclonal B cells, and interfollicular histiocytes. Distribution of T and B cells (immunoarchitecture) was essentially normal and similar in all cases, regardless of HIV status. Syphilis produces essentially identical findings in lymph nodes in both HIV-positive and HIV-negative patients. The morphologic findings described should prompt evaluation for infection with Treponema pallidum and, in light of the current epidemic, HIV.