HIV, measles, and syphilis: histopathologic characteristics of lymphatic system involvement of three reemerging infectious diseases.

The resurgence of measles, syphilis, and HIV presents a significant threat to global health, especially in the wake of the COVID-19 pandemic. These three infections involve lymph nodes and have unique pathologic findings in lymph nodes. We explore the pathological and clinical characteristics of these infections, focusing on their involvement of lymph nodes and their pathologic diagnosis in lymph node specimens. For HIV, lymph nodes are sites of viral replication and reservoirs, and the disease demonstrates multiple patterns within lymph nodes. The recent increase in measles, due in part to declining vaccination rates, signals the need for pathologists to be able to identify the characteristic Warthin-Finkeldey cells present in lymph node specimens. Syphilis, a reemerging sexually transmitted infection, often presents with lymphadenopathy and can mimic other conditions, complicating clinical diagnosis. By revisiting well-established findings and presenting new insights into the histopathological changes within lymphoid tissues, this review provides essential knowledge for pathologists and clinicians to improve diagnostic accuracy and treatment outcomes.