Hodgkin's lymphoma and disseminated Mycobacterium avium complex (MAC) infection share similar clinical features; both may affect human immunodeficiency virus (HIV)-positive individuals. We discuss a patient with poorly controlled HIV-infection presenting with chest sepsis, dyspnoea and weight loss. Whilst the initial working diagnosis was that of MAC infection, pathology results had not met diagnostic criteria. Lymph node biopsy instead revealed classical Hodgkin's lymphoma. We discuss the role of radiological examination in cases of diagnostic uncertainty.