I] Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder resulting from primary or acquired immune dysfunction. In adults, HLH is most frequently associated to infections, autoimmune diseases, and lymphomas, although Hodgkin lymphoma (HL) has been less frequently described. This immune activation leads to a variety of clinical and laboratory features, including pancytopenia, which makes bone marrow examination an important tool in order to identify possible trigger factors for HLH.
II] Case presentation: A 53 year-old white female, was referred to the Hospital das Clínicas de Botucatu –UNESP (São Paulo, Brazil) with a 4-day history of mental confusion. She had no palpable lymphadenomegaly, hepatosplenomegaly or abdominal mass. Complete blood count showed markedly pancytopenia. Lactate dehydrogenase was normal and serum ferritin was 9.621 mg/dl. Bone marrow (BM) cytology evaluation showed markedly hemophagocytosis and some large cells were identified as “Owl Eye Cell” and “Mononuclear Hodgkin’s Cells”. The bone marrow clot evaluation showed frequent epithelioid granulomas, without necrosis, and bi-nucleated and mononuclear cells with large nuclei and evident nucleoli, featuring classic Reed-Sternberg cells and Hodgkin’s cells. Immunohistochemistry confirmed the diagnosis of bone marrow infiltration by HL with granulomatous reaction. The Ziehl-Neelsen and Grocott-Gomori stains were negative.
III] Discussion: BM cytological evaluation is immediately required in cases of pancytopenia for diagnostic purpose, regardless the level of blood counts. Especially in HLH, it is part of a systematic front-line clinical investigation for possible immune triggers. Epithelioid granulomas in BM or lymph nodes of patients with a nonspecific clinical presentation is a diagnostic challenge as it can be associated with a variety of autoimmune, inflammatory and neoplastic conditions. HL can present with granulomas in about 14% of cases, although it is unusually seen in BM biopsy. In this context, a careful morphological analysis with immunohistochemistry study is highly recommended considering that the absence of a typical HL presentation can sometimes postpone diagnosis and compromise disease outcome. IV] Conclusion: This case highlights the importance of prompt investigation of pancytopenia in the context of HLH, with an early diagnosis of HL being made by BM cytology in a patient with no other symptoms that could suggest lymphoma.