Lupus Enteritis With Concomitant Genitourinary Involvement as the Initial Presentation of Juvenile-Onset Systemic Lupus Erythematosus.

BACKGROUND Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with a strong predilection for women of reproductive age. Although uncommon, juvenile-onset SLE (jSLE) is usually associated with more severe disease than adult-onset SLE. The simultaneous occurrence of gastrointestinal and genitourinary manifestations, such as lupus enteritis, cystitis, and epididymo-orchitis, is exceedingly rare. We describe an unusual presentation of jSLE in an adolescent male patient with combined gastrointestinal and genitourinary involvement. CASE REPORT We report a previously healthy 16-year-old male patient who presented with a 2-month history of high-grade fever, weight loss, and lymphadenopathy, initially diagnosed as pyrexia of unknown origin. Further evaluation confirmed jSLE with multiorgan involvement, including lupus nephritis, enteritis, peritonitis, cystitis, and immune-mediated epididymo-orchitis. This was supported by imaging, which revealed small-bowel wall thickening, ascites, and diffuse bladder wall thickening on abdominal computed tomography, as well as bilateral epididymo-orchitis on scrotal ultrasonography, findings consistent with lupus enteritis, peritonitis, and cystitis. Clinical and biochemical responses were achieved after induction with intravenous methylprednisolone pulses, followed by gradual corticosteroid tapering and high-dose intravenous cyclophosphamide. Remission maintenance with hydroxychloroquine and mycophenolate mofetil enabled corticosteroid discontinuation and complete symptom resolution at follow-up. CONCLUSIONS This case demonstrates a rare occurrence of SLE in a male adolescent with concurrent gastrointestinal and genitourinary manifestations. Recognizing these atypical features is vital when evaluating abdominal pain and urinary symptoms in patients with SLE. Early diagnosis and prompt initiation of immunosuppressive therapy remain the cornerstone for minimizing the risk of long-term morbidity and are associated with a more favorable prognosis.