Distinguishing between a primary malignancy and a metastasis can be challenging in some cases. Herein, we describe 2 cases of gastric lesions that were endoscopically sampled and ultimately found to be metastatic from a renal-cell carcinoma. In both cases, the gastric metastases were endoscopically homomorphic to the primary organ (the kidney); i.e., grossly resembling and thus providing an endoscopic clue as to the primary tumor source. We report on the evaluation of obscure metastatic gastric involvement of malignancy and present the concept of homomorphism as a potential diagnostic clue in determining the source of unknown and often unsuspected primary malignancy.

中文翻译：

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作为体内诊断线索的“同型”肿瘤转移：转移至胃的肾细胞癌病例系列。

在某些情况下，区分原发性恶性肿瘤和转移瘤可能具有挑战性。本文中，我们描述了2例胃镜下胃部病变的病例，最终发现它们从肾细胞癌转移。在这两种情况下，胃转移在内镜下均与原发器官（肾脏）同型。即，大致类似于并因此提供了关于原发肿瘤来源的内窥镜提示。我们报告了对转移性胃癌隐匿性恶性评估的评估，并提出了同态性的概念作为确定未知且通常不可怀疑的原发性恶性肿瘤来源的潜在诊断线索。