胸腺瘤在臨床表現上會伴隨各種不同附腫瘤性症候群，如重症肌無力症，純紅血球再生不良或低免疫球蛋白血症。附腫瘤性腎病在惡性腫瘤的臨床表現上是很少見的。因為缺乏特定的臨床表徵，我們容易忽略這種狀況。根據從前的文獻，大約有百分之二胸腺瘤病人在臨床上有附腫瘤性腎病，腎病症候群是其中一種表現。我們報導兩個在台灣胸腺瘤的病人，臨床上也有腎病症候群的診斷。腎臟切片診斷其中一個是局部性腎絲球硬化症，另一個是微小病變性腎病。第一個報告案例中，腎病症候群出現在胸腺瘤診斷之前，而另一個病人的腎病症候群出現在胸腺瘤治療之後。因為容易忽略的臨床表現以及對治療的影響，治療胸腺瘤病人時，如果臨床上出現全身水腫或低蛋白血症，都應該要考慮腎病症候群的可能性，並且治療上也需要多團隊的協助。另外值得注意的是，腎病症候群可能是胸腺瘤病人最初的臨床表現。

Thymoma is associated with a wide variety of paraneoplastic syndromes such as myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. Paraneoplastic glomerulonephritis is a rare clinical presentation of malignancy. This condition often goes undetected as it has no specific clinical symptoms and signs. Approximately 2% of thymoma patients have been reported to have paraneoplastic glomerulonephritis, and the nephrotic syndrome has been shown to be a clinical manifestation of the disorder. We report two cases diagnosed to have thymoma and nephrotic syndrome. Renal biopsy showed that one case had focal segmental glomerulosclerosis, whereas the other had minimal change disease. In case 1, the nephrotic syndrome was diagnosed before thymoma was detected, while in case 2, the symptomatic nephrotic syndrome occurred after thymoma treatment. Because parathymic nephropathy often remains undiagnosed and interferes with treatment, the possibility of the nephrotic syndrome should always be considered throughout the course of thymoma management, particularly in patients who also present with anasarca or hypoalbuminemia. A multidisciplinary approach is needed. Besides, it is to be noted that the nephrotic syndrome may be the initial presentation of thymoma.