Parry-Romberg syndrome with ipsilateral hemipons involvement presenting as monoplegic ataxia.

Parry-Romberg syndrome (PRS) is a rare, acquired disorder characterized by progressive unilateral facial atrophy of the skin, soft tissue, muscles, and underlying bony structures that may be preceded by cutaneous induration. It is sometimes accompanied by ipsilateral brain lesions and neurological symptoms. Here we present the case of a 10-year-old girl with right-sided PRS and recurrent monoplegic ataxia of the left leg. At 4 years of age, she presented with localized scleroderma over the right parietal region of her scalp; her face gradually became asymmetric as her right cheek atrophied. Brain magnetic resonance imaging revealed hemiatrophy of the face and skull base, and T2-weighted images showed increased signal in the right hemipons and hemicerebellar peduncle. Magnetic resonance angiography findings were unremarkable. She was treated with oral prednisolone, and her recurrent gait ataxia diminished within 2 months of the follow-up period. To the best of our knowledge, this is only the second case of PRS presenting with an abnormal involvement of the ipsilateral hemipons.