[Amyopathic dermatomyositis with interstitial pneumonia: effective treatment with cyclophosphamide pulse therapy]

A 42-year-old man was admitted to our hospital because of dyspnea on exertion, skin eruptions on the face and extremities, and interstitial shadows mainly in the lower fields of both lungs. Characteristic skin lesions and skin biopsy findings without muscle symptoms or elevated CPK resulted in a diagnosis of amyopathic dermatomyositis (ADM). Thoracoscopic lung biopsy specimens disclosed BOOP-type interstitial pneumonia. Oral prednisolone (PSL) was initiated at 60 mg/day and gradually tapered. However, because his respiratory symptoms and laboratory findings deteriorated, the patient underwent 5 courses of cyclophosphamide (CPA) pulse therapy. Following improvement of his subjective symptoms, arterial blood gas data, and respiratory functions, the patient was discharged and placed on oral PSL and CPA. CPA was discontinued 18 months later. The patient has continued to receive PSL (5 mg/day) and has been in good condition for 3 years. Though the prognosis for interstitial pneumonia associated with ADM is reported to be poor, our patient represented a rare case of BOOP-type interstitial pneumonia brought into remission by CPA pulse therapy.