Lupus erythematosus cells in bone marrow: the only clue to a previously unsuspected diagnosis of systemic lupus erythematosus.

BACKGROUND Systemic lupus erythematosus (SLE) is an autoimmune multisystem disease characterized by the development of antinuclear antibodies. Nowadays considered outdated, lupus erythematosus (LE) cell preparation served as a screening test for SLE for decades. However, the importance of discovering LE cells on routine cytology cannot be overemphasized. CASE We report the case of a 30-year-old female in whom bone marrow aspiration (BMA) was performed during an investigative workup for pyrexia of unknown origin. The observation of LE cells in direct bone marrow smears (without the use of an anticoagulant) raised the suspicion of SLE, which was later confirmed by antinuclear antibody testing. CONCLUSION In the present case, LE cells were observed on BMA performed for the investigation of fever of unknown origin. The unexpected observation of LE cells in BMA smears emphasizes the fact that good morphological observation of marrow aspirates can provide crucial clues to a previously unsuspected diagnosis.