RHUPUS SYNDROME REVEALED BY LIFE-THREATENING AUTOIMMUNE CYTOPENIAS AND ASSOCIATED WITH A RENAL NON-LANGERHANS CELL HISTIOCYTIC GRANULOMATOUS INFILTRATE: A CASE REPORT AND UPDATED LITERATURE REVIEW

Soukaina Mounsif*, Mina Moudatir, Khadija Echchilali, Meriem Benzakour, Hassan El Kabli

Background: Rhupus syndrome is a rare overlap condition combining features of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). While hematologic abnormalities are frequent in SLE, severe bleeding secondary to profound immune thrombocytopenia (ITP) as a presenting manifestation of rhupus is exceptional. Concomitant histiocytic disorders are rarely described. Case presentation: A 42-year-old Moroccan woman was admitted for severe hemorrhagic syndrome (Khellaf bleeding score 20) with active inflammatory polyarthritis. She had pallor, lower-limb purpura, malar rash, and fusiform finger swelling with positive squeeze test. Labs showed aregenerative normocytic anemia (Hb 6 g/dL), profound thrombocytopenia (<10,000/mm³), and positive direct Coombs test; bone marrow was normal and viral serologies were negative. Immunology revealed ANA 1:640, anti-dsDNA positivity, rheumatoid factor 60 U/mL, anti-CCP 50 U/mL, and CRP 30 mg/L. Ultrasound confirmed active polyarthritis of wrists and hands. Rhupus syndrome was diagnosed (2010 ACR/EULAR RA score 7; 2019 ACR/EULAR SLE score 16). Extension work-up showed normal renal function and negative proteinuria but low complement and anti-dsDNA persistence, consistent with moderate SLE activity. CT scan revealed a pelvic renal mass-like lesion; biopsy demonstrated a CD68-positive granulomatous histiocytic infiltrate consistent with non-Langerhans cell histiocytosis. She received IV methylprednisolone pulses followed by oral prednisone, plus azathioprine and hydroxychloroquine, with rapid clinical and biological improvement and marked radiological regression of the renal lesion. Conclusion: This case highlights a rare rhupus presentation dominated by life-threatening autoimmune cytopenias and an unusual renal histiocytic granulomatous infiltrate responding to immunosuppression. It underscores the need for early recognition, careful differential diagnosis, and multidisciplinary management.