[A case of idiopathic fibrosing mediastinitis presented with bilateral pleural effusion].

A case is reported of a 56-year-old male who presented with bilateral pleural effusion as an initial manifestation of idiopathic fibrosing mediastinitis. The patient showed shortness of breath with severe loss of vital capacity and weight loss. A mediastinal mass surrounding the thoracic aorta and bilateral pleuritis was identified by the chest CT scan. The mass extended, along the abdominal aorta, to the upper portion of retroperitoneum. Laboratory data showed elevated levels of C-reactive protein (CRP), erythrocyte sedimentation ratio (ESR), and IgG. Biopsy of the mediastinal and the pleural mass showed adipose tissue and fibrosis with mild perivascular inflammatory infiltration. A diagnosis of idiopathic fibrosing mediastinitis was made, and 40 mg/day of prednisolone was administered. Although CRP and ESR was normalized, the mass size and vital capacity were almost unchanged.