Brucella melitensis bacteraemia with lymphoma-like generalised lymphadenopathy and probable secondary haemophagocytic lymphohistiocytosis under biopsy constraints: a case report

Front Immunol. 2026 Oct 21;17:1975515. doi: 10.3389/fimmu.2026.1975515. eCollection 2026.

ABSTRACT

BACKGROUND: Brucellosis can resemble lymphoma when lymphadenopathy accompanies cytopenias and systemic inflammation. Associated secondary haemophagocytic lymphohistiocytosis (HLH) adds to the diagnostic difficulty.

CASE PRESENTATION: A 68-year-old man presented with anorexia, generalised lymphadenopathy, splenomegaly, cytopenias, and hepatic and renal dysfunction. Fever developed on the first hospital evening and reached 41 °C on day 2. Empirical antibiotics and corticosteroids were started before microbiological confirmation. Severe thrombocytopenia complicated biopsy planning, and the patient declined tissue sampling because of financial hardship and concern about physical harm. Blood cultures collected on day 2 yielded Brucella melitensis, reported on day 6. Doxycycline and rifampicin were started, and methylprednisolone was continued. Five HLH-2004 criteria and a retrospective HScore of 234 supported probable secondary HLH. Fever and some laboratory abnormalities improved during empirical treatment, but cytopenias persisted at discharge on day 10. Follow-up blood tests approximately 1 month after discharge showed recovery of white-cell, neutrophil and platelet counts to reference ranges, although anaemia persisted. At approximately 15 months, the patient reported feeling well but declined further laboratory testing and imaging.

CONCLUSION: Blood cultures identified B. melitensis infection in a patient with lymphoma-like findings and probable secondary HLH. Microbiological identification and serial assessment guided treatment when tissue sampling was declined.

PMID:42984588 | PMC:PMC13730908 | DOI:10.3389/fimmu.2026.1975515