Parry-Romberg Syndrome Associated With En Coup De Sabre: A Clinical Case Report.

Parry-Romberg syndrome (PRS), also known as progressive facial hemiatrophy, is a rare neurocutaneous disorder characterized by progressive, unilateral atrophy of the facial tissues. It usually appears during childhood or early adulthood; however, adult-onset cases are increasingly being recognized. PRS significantly overlaps with localized scleroderma, especially the en coup de sabre (ECDS) subtype, indicating a common pathophysiological mechanism. We present a 52-year-old female patient with adult-onset PRS associated with ECDS. The patient was first diagnosed with localized scleroderma in 1999, when she developed subtle atrophic changes in the right side of her face. Over two decades, the atrophy gradually advanced, leading to marked facial asymmetry. Re-evaluation in 2023 showed right hemifacial atrophy with a linear "sword stroke" lesion over the forehead that is a characteristic of ECDS. Laboratory tests, imaging, ophthalmologic evaluation, and skin biopsies confirmed PRS with linear scleroderma. To address the progressive functional and aesthetic impairments, systemic treatment with methotrexate was initiated to halt disease progression, with regular follow-ups scheduled for monitoring. This rare case of adult-onset PRS evolving from localized scleroderma highlights the need for high clinical suspicion in adults with progressive hemifacial atrophy, especially with ECDS. Early diagnosis and timely immunosuppressive treatment are crucial to limit disease progression and maximize patient outcomes.