Neonatal cardiac lupus is a rare, passively acquired autoimmune disease. We report a case of in utero myocarditis, confirmed postnatally, with papillary muscle rupture and severe tricuspid regurgitation after birth in the absence of conduction disturbances. Tricuspid repair was successfully performed with polytetrafluoroethylene neochordae. In this article, we discuss the pathophysiology, medical and surgical management, and implications at follow-up in this unique scenario.