Malignant Thymoma Presenting as Nephrotic Syndrome

Abstract

SESSION TITLE: Disorders of the Mediastinum 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Thymoma is a rare mediastinal tumor associated with different paraneoplastic syndromes, like myasthenia gravis and pure red cell aplasia. Association with nephrotic syndrome quite rare (<1%). CASE PRESENTATION: 61 female with history of stage II breast cancer in 2009 status post mastectomy and chemoradiaton on letrozole. Patient presented to the emergency room in late 2013 with dyspnea. CT Chest revealed anterior mediastinal mass for which she had non diagnostic biopsy. Stable on follow up until 2017 when she presented with generalized swelling. Positron Emission Tomography (PET) demonstrated moderate bilateral effusions, enlarging anterior mediastinal mass 5.3 x 2 cm and new PET positive pleural based lesions extending down the mediastinal pleura anteriorly. 24 hour urine showed 9 gram proteinuria. Serum albumin 1.2mg/dl, creatinine 1.43 mg/dl. Anti nuclear antibody (ANA),rheumatoid factor ,rapid plasma reagin, hepatitis panel , HIV all negative. Renal biopsy showed minimal change disease. Steroid was started. CT guided biopsy of mediastinal mass was non diagnostic. Resection followed showing Masaoka stage IV a, WHO type B3 thymona. Post resection kidney function ,albumin and generalized swelling improved but proteinuria persisted. DISCUSSION: Disorder of thymus may disrupt regulatory function of T-cell mediated immunity. It has been postulated that secretion of lymphokines that increase the glomerular basement membrane permeability is central to pathogenesis of nephrotic syndrome. Minimal change disease is the common nephropathy followed by membranous nephropathy, cresentic glomerulonephritis, focal segmental glomerulosclerosis. Majority of WHO B2 thymoma have minimal change disease while WHO B3 havemembranous nephropathy. Our patient had B3 disease and minimal change disease. In almost half of patients, nephropathy occurrs several months to years after diagnosed and treated thymic disease. In some thymoma is discovered long after the nephropathy and few have renal and mediastinal disease diagnosed simulatenously. Surgical resecion of thymoma has led to remission of the nephrotic syndrome in majority of patients and occasionally return of the massive proteinuria has predicted the recurrence of thymoma. CONCLUSIONS: Thymoma is a rare and associated nephropathy is even rare. It is important to be vigilant about the association, as nephropathy can signal thymoma early in the course. Reference #1: Thymoma and the nephrotic syndrome; Cancer 1980; Posner et al. DISCLOSURE: The following authors have nothing to disclose: Bikash Bhattarai, Robert Love, Kevin Kovitz No Product/Research Disclosure Information