Anaplastic Large Cell Lymphoma Presenting as Haemophagocytic Lymphohistiocytosis with Underlying Coxiella burnetii and Bartonella henselae Seropositivity.

A 44-year-old woman with no significant medical history presented with a 3-week history of high-grade fevers, fatigue and shortness of breath. Laboratory investigation was significant for lymphopenia and thrombocytopenia which progressively worsened during her hospital stay, along with new-onset anaemia, and elevated ferritin, transaminase and triglycerides. A computerized tomography (CT) scan of the abdomen revealed retroperitoneal lymphadenopathy. A bone marrow biopsy confirmed the diagnosis of haemophagocytic lymphohistiocytosis (HLH). Extensive infectious work-up revealed high IgG titres for Bartonella henselae and Coxiella burnetii. Interestingly, the left supraclavicular node was negative for both microbes by polymerase chain reaction (PCR), but the biopsy revealed anaplastic large T-cell lymphoma. LEARNING POINTS: Haemophagocytic lymphohistiocytosis (HLH) is an important differential diagnosis to consider for fever of unknown origin in adults, especially in the setting of pancytopenia and hyperferritinaemia.Q fever resulting from Coxiella burnetii can cause HLH and is also postulated to increase the risk of lymphoma.Bartonella henselae infection can also trigger HLH, but the risk of lymphoma following infection by B. henselae is unknown. © EFIM 2020.