Herpes simplex lymphadenitis in an immunocompetent patient: diagnostic pitfalls on cytology and review of literature

Herpes simplex virus (HSV) lymphadenitis is an uncommon manifestation in immunocompetent individuals and is rarely seen as an isolated presentation. This report describes the case of a 23-year-old immunocompetent female who presented with inguinal lymphadenopathy and a painful labial rash. Fine-needle aspiration cytology of the inguinal lymph node revealed an inflammatory background with multinucleated giant cells, ground-glass nuclei, and occasional intranuclear inclusions. Immunohistochemistry confirmed HSV type 2 infection, which was supported by serological positivity. The patient responded well to acyclovir therapy, with complete resolution and no recurrence at 6-month follow-up. HSV lymphadenitis may mimic other viral or granulomatous infections histologically, making cytomorphologic recognition crucial. Thus, HSV should be considered in the differential diagnosis of lymphadenopathy and a detailed hematologic and immunologic workup should be done due to its known association with hematologic malignancies.