腎臟囊腫並不少見，其中約有千分之五是惡性的，腎臟假性囊腫則非常少見。骨外造血則通常是長期造血功能不良所產生的代償現象。以往文獻從未報導過腎臟假性囊腫合併骨外造血的病例。這篇報告在此為您提供一個病例和簡單的討論。做為日後類似病例鑑別論斷的參考。

Pseudocyst is defined as a cystic lesion with no lining epithelium. It is rearely found in the kidney. Extramedullary hematopoiesis is usually secondary to hematological problem as a compensatory mechanism for insufficient erythrocyte formation. It is even rare in the renal pseudocyst with extramedullary hematopoiesis. To our knoweledge, there was no report of such combination in the English literatures. Herin, we present a case.