Epithelioid pleural mesothelioma concurrently associated with miliary pulmonary metastases and minimal change nephrotic syndrome - A hitherto undescribed case

Malignant pleural mesothelioma (MPM) is the aggressive disease typically spreading along the pleural surface and encasing the lung, leading to respiratory failure or cachexia. Rare cases with atypical clinical manifestation or presentation have been reported in MPM. We experienced a unique case of MPM concurrently associated with miliary pulmonary metastases and nephrotic syndrome. A 73-year-old Japanese man with past history of asbestos exposure was referred to our hospital for the investigation of the left pleural effusion. Chest computed tomography showed thickening of the left parietal pleura. Biopsy specimen of the pleura showed proliferating epithelioid tumor cells, leading to the pathological diagnosis of epithelioid MPM with the aid of immunohistochemistry. After the diagnosis of MPM, chemotherapy was performed without effect. Soon after the clinical diagnosis of progressive disease with skull metastasis, edema and weight gain appeared. Laboratory data met the criteria of nephrotic syndrome, and renal biopsy with electron microscopic examination revealed the minimal change disease. Steroid therapy was started but showed no effect. Around the same time of onset of nephrotic syndrome, multiple miliary lung nodules appeared on chest CT. Transbronchial biopsy specimen of the nodules showed the metastatic MPM in the lung. The patient died because of the worsening of the general condition. To our knowledge, this is the first case of MPM concurrently associated with multiple miliary pulmonary metastases and nephrotic syndrome.