CHEST Guidelines-Case-of-a-57-Year-Old-Man-With-Malignant-Mesotheli

Case-of-a-57-Year-Old-Man-With-Malignant-Mesotheli

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A 57-year-old man with malignant pleural mesothelioma experienced worsening dyspnea and a new dry cough. His history included asbestos exposure from his time in the Navy and stage IIIB right-sided malignant pleural mesothelioma diagnosed 11 months prior. The patient displayed acute renal failure and had received chemotherapy, with recent imaging revealing new miliary nodules in the left lung.<br /><br />Physical examination showed decreased air entry and dullness in the right lung, with imaging confirming diffuse nodular opacities in the left lung and unchanged right-sided pleural disease. Bronchoscopy and biopsy confirmed epithelioid mesothelioma cells in the lung parenchyma. Differential diagnosis ruled out infections like tuberculosis and side effects from Bevacizumab, leading to a diagnosis of miliary metastasis of malignant pleural mesothelioma (MPM).<br /><br />MPM is a rare, aggressive cancer mostly resulting from asbestos exposure, with typical progression through local invasion rather than hematogenous spread. Only a few cases have documented miliary metastasis. This case highlights unusual hematogenous metastasis in mesothelioma, seen as miliary nodules on imaging. Attempts to treat included starting nivolumab, but the patient succumbed to respiratory failure a month after discharge.<br /><br />Imaging in MPM often shows pleural thickening and effusion, with late-stage spread affecting the contralateral lung and other organs. Hematogenous metastasis, though rare, can manifest in a miliary pattern. Pathological examination using immunohistochemistry is crucial for differentiating MPM from other similar conditions. Specifically, the immunohistochemical profile ruled out other carcinomas but confirmed MPM by showing positive markers like cytokeratin 5/6, while negative for others typical in adenocarcinomas. This case underscores the importance of considering miliary metastasis in patients with stable pleural disease and new diffuse nodular patterns on imaging.

Keywords

malignant pleural mesothelioma

asbestos exposure

miliary metastasis

epithelioid mesothelioma

respiratory failure

immunohistochemistry

chemotherapy

pleural thickening

hematogenous spread

Navy