Pneumomediastinum, pneumatosis intestinalis and pneumoperitoneum in a patient with polymyositis: case-based review.

Pneumomediastinum (PnM), pneumatosis intestinalis (PI), and pneumoperitoneum (PP) are rare complications of inflammatory myositis. We present a 59-year-old polymyositis (PM) patient who experienced all three complications simultaneously. The patient who presented with proximal muscle weakness, dysphagia, and weight loss was diagnosed with PM due to elevated muscle enzymes and consistent electromyography and muscle biopsy with inflammatory myopathy. On the 45th day of her immunosuppressive treatment, PnM, PI, and PP were detected incidentally in 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) scan performed for severe weight loss and treatment-resistant severe disease. Since the patient had no symptoms or signs of PnM and PP, no additional intervention was applied to the current treatment, and spontaneous regression was observed in the follow-up. In addition to this case, we reviewed patients with PM who developed PBM, PP, and PI in the literature.