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 Nowadays considered outdated, lupus erythematosus (LE) cell preparation served as a screening test for SLE for decades.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.