A 50-year-old male without a relevant medical history came to the emergency department with fever, muscle pain and fatigue without any localising symptoms. Blood and urine cultures remained negative. Laboratory work- up showed elevated liver enzymes and lactate dehydrogenase; Epstein-Barr virus (EBV) serology was negative. Additional imaging showed a splenomegaly and cervical, axillary, mediastinal and hilar lymphadenopathy. Pathological examination of one of the lymph nodes and bone marrow biopsy revealed a peripheral T-cell non-Hodgkin’s lymphoma not otherwise specified. Before the start of treatment he was asymptomatic, the laboratory results had normalised and the EBV polymerase chain reaction was strongly positive. Computed tomography scan was repeated and showed complete remission of the lymphadenopathy and normalised spleen volume. Follow-up bone marrow analysis including clonal rearrangement of the T-cell receptor after three months and one year revealed a decreasing clonal T-cell population (41%, 39% and 11% respectively). In conclusion, this was an extreme course of an EBV infection. The clinical relevance of the remaining small monoclonal T-cell population detectable in the bone marrow is unclear.