As a result of development in medical diagnostic technology, the incidence of double primary cancer is increasing. In case that one primary cancer was identified by pathologic finding and has suggestive multiple metastatic lesions of the cancer, it is often difficult that the lesions are considered as another synchronous primary malignancy, not as metastasis of primary cancer. Here, we report a rare case of synchronous double primary renal cell carcinoma that was diagnosed initially as metastatic duodenal adenocarcinoma. A 66-year-old man presented with a palpable abdominal mass. Abdominal computed tomography showed duodenal wall thickening and hypervascular masses in the liver and left kidney. Esophagogastroduodenoscopy revealed an ulcerative lesion in the duodenal bulb, and endoscopic biopsy identified moderately-differentiated adenocarcinoma. We regarded the findings as duodenal adenocarcinoma with metastasis to liver and kidney. So he was treated with fluoropyrimidine-based chemotherapy for the diagnosis of duodenal adenocarcinoma with liver and renal metastases. After 10 months, he developed a right forearm mass. Morphological and immunohistochemical analysis of an incisional biopsy of the forearm mass were consistent with a diagnosis of metastatic renal cell carcinoma. Even when there is a pathologically confirmed malignancy, clinicians must consider the possibility of synchronous double primary malignancy in metastatic lesions.

신장암은 비뇨기과 악성 종양 중 두번째로 많은 빈도를 차지하며 다양한 임상 양상을 갖는다. 그 중 약 1/3은 진단 당시 전이성 암으로 발견된다. 3,4 전이가 호발하는 부위는 폐, 뼈, 림프절과 간 등을 포함하며 드물게 췌장으로 전이를 동반한다고 알려져 있다. 8 췌장 전이의 경우 반수 이상에서는 증상이 없고 증세를 보이는 경우는 복통, 체중 감소, 지방변으로 내원하며 드물게 담도 폐쇄에 의한 증상으로 내원하게 된다. 출혈로 내원하는 경우도 전체의 40% 정도가 되지만 췌장의 자연 출혈로 인해 담관염을 유발하는 경우는 드물다. 10 저자 들은 신장암의 전이성 췌장암과 이로 인한 출혈이 담관염을 유발할 수 있음을 보여주는 흥미로운 증례를 경험하였기에 이를 문헌고찰과 함께 보고하는 바이다.

Everolimus is a secondary medication for metastatic renal cell carcinoma when vascular endothelial growth factor inhibitor treatment fails. Everolimus is reported to cause a variety of metabolic complications but complications in the eye are rare. Although serious eye complications have not been reported, secondary complications may result from the metabolic complications. We observed a case in which central retinal vein occlusion occurred, probably caused by metabolic complications following Everolimus treatment of RCC. We report this case.