Angioimmunoblastic T-cell Lymphoma: A Mimic for Lupus.

New-onset systemic lupus erythematosus (SLE) is uncommon in elderly patients. We report the case of a 71-year-old woman who was diagnosed with SLE based on clinical manifestations of fever, alopecia, bicytopenia, hepatomegaly, lymphadenopathy, glomerulonephritis, positive antinuclear antibody (ANA) and anti-double stranded DNA (anti-dsDNA) antibody. Renal biopsy was consistent with lupus nephritis and excision biopsy of a right inguinal lymph node was initially reported as having features of reactive hyperplasia. However, a more careful review of the lymph node biopsy subsequently confirmed a concurrent angioimmunoblastic T-cell lymphoma. This case illustrates the importance of investigating secondary causes and possible alternative diagnoses in patients who present with atypical features of connective tissue disease, and the challenges in diagnosing a rare form of lymphoma. LEARNING POINTS: A thorough work-up for secondary causes and careful evaluation to exclude possible alternative diagnoses is important in cases of elderly-onset lupus.The disease presentations of lupus and haematological malignancies such as lymphoma may mimic each other and differentiation between the two can be clinically challenging; lupus can be associated with cytopenias, hepatomegaly and lymphadenopathy, but the degree of severity and the context of the clinical presentation need to be considered carefully before attributing these features to it.As some lymphomas are rare and difficult to diagnose, if there is a high clinical suspicion despite negative histological studies, discussion with the pathologist is important and a review of histology should be sought. © EFIM 2020.