Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus (EBV)-driven lymphoproliferative disease that usually arises in the context of reduced immunological surveillance. Based on histology, two forms of the disease are recognized, namely low-grade and high-grade LYG. Clinically, LYG universally involves the lungs and, frequently, also the skin, central nervous system, liver, and kidneys. Here, we present the case of a 55-year-old woman with a difficult-to-diagnose low-grade LYG with symptomatic lung involvement, who concomitantly was newly diagnosed with human immunodeficiency virus (HIV) infection. Rapid immune recovery achieved through antiretroviral therapy led to a complete and sustained clinical and radiological remission of LYG.