Lupus erythematosus cells in vivo (pleural fluid): An unusual presentation of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which organs and cells undergo damage mediated by tissue-binding autoantibodies and immune complexes. In earlier times, the diagnosis of SLE included the lupus erythematosus (LE) cell assay. Though the LE cell test has now been declared obsolete, its presence carries importance especially when one finds LE cells in vivo. We report an unusual case of SLE in a 27-year-old female who presented with acute shortness of breath, fever, and cough. On initial outpatient basis investigations, the patient was detected with anemia, bilateral pleural effusion, synovitis, and juxta-articular swelling of the soft tissues. Her chest radiograph effusion was tapped and sent to the cytopathology laboratory. The cytological examination of the pleural fluid revealed numerous LE cells that prompted the diagnosis of SLE. Autoimmune serology techniques such as antinuclear antibody staining have replaced the LE cell assay. However, as presented in this report and found in a review of the literature, the in vivo finding of LE cells by cytopathology can provide an important clue to the diagnosis of SLE. This case is interesting because although pleural effusion is common, very rarely LE Cells are encountered in vivo. There are very few case reports of SLE diagnosed in a cytopathology laboratory. Moreover, our finding of LE cells in the pleural fluid of the patient led to swift diagnosis, helped rule out the differential diagnosis of rheumatoid arthritis and prompted the immediate initiation of treatment. Furthermore, our case highlights the fact that no matter the advances in diagnostic testing methods, practitioners must always keep an eye open for the basic pathognomonic findings of diseases