Case Presentation: A 78 year old male with diabetes mellitus, smoking, cirrhosis due to nonalcoholic steatohepatitis, and recurrent left-sided pleural effusions presented with volume overload and oliguria. His serum creatinine had been stable at a baseline of 0.8 mg/dL for years, but in the past month, his serum creatinine progressed to 5.3 mg/dL. 24-hour urinary protein was greater than 4 grams with bland sediment. HIV, hepatitis C virus, serum and urine electrophoresis, and antineutrophil cytoplasmic antibody were all negative. Renal biopsy showed severe acute tubular necrosis and minimal change disease (MCD). As this was adult onset MCD, a paraneoplastic syndrome was suspected. PET imaging showed left pleural thickening and effusion with supraclavicular, paratracheal, and hilar lymphadenopathy. A thoracentesis with cytology produced a transudative effusion without malignant cells. An endobronchial ultrasound-guided biopsy revealed malignant epithelioid mesothelioma. The patient did not initially report a history of mesothelioma exposure, but later remembered his father was a shipyard worker and would often bring home asbestos-laden clothing. Unfortunately, the patient had poor functional status, and once mesothelioma was diagnosed, he opted for hospice care.
Discussion: In adults, MCD accounts for less than 10% of all nephrotic syndromes, and is diagnosed with renal biopsy. Secondary etiologies for MCD include infections, drugs, and malignancy, particularly hematologic but rarely solid tumors. There are case reports of thymoma, renal cell carcinoma, colorectal adenocarcinoma, and mesothelioma associated with MCD, as well as reports of simultaneous MCD and acute tubular necrosis. The pathophysiology of the development of MCD in patients with mesothelioma is unknown. The management of MCD in this setting involves treating the underlying malignancy.
Mesothelioma is a tumor of mesothelial cells associated with asbestos exposure. The diagnosis and treatment of mesothelioma are challenging as patients are typically diagnosed in the later stages of the disease. Thoracentesis with cytology yields the diagnosis in less than 25% of cases, and even pleural biopsy is diagnostic in less than 40% of cases. Endobronchial ultrasound-guided biopsy or video-assisted thoracoscopic surgery is typically required.
Conclusions: Rapidly progressive renal failure requires expedited diagnosis with renal biopsy. Furthermore, this case highlights the importance of considering an underlying malignancy in adults who present with MCD. Clinicians must pursue a tissue diagnosis, despite initially reassuring results such as a transudative pleural effusion. Mesothelioma is often diagnosed via endobronchial ultrasound-guided biopsy or video-assisted thoracoscopic surgery because less invasive testing is so often negative. Our patient did not report a typical asbestos history, but even minimal exposure can predispose individuals to this type of aggressive cancer.