Tumor-to-Tumor Metastasis of Lung Cancer to Kidney Cancer: A Review of the Literature and Our Experience

Abstract

Tumor-to-tumor metastasis (TTM) is a rare phenomenon documented in patients with multiple primary cancers. This condition is defined as a metastasis between two true primary tumors. The most frequently reported recipient tumor is renal cell carcinoma (RCC), and the lung carcinomas are the most common metastatic tumor donors. Therefore, this paper attempts to address the current gap in knowledge about this rare phenomenon. The first part of this review outlines the recently proposed models and mechanisms involved in the TTM process. The second part then summarizes and analyzes previous case reports in the literature. We also present our experience with the case of lung cancer that metastasized into RCC. Given the sporadic incidence of TTM, no specific management guidelines exist. Therefore, considering TTM in patients with multiple primary tumors is important as it could potentially modify the oncological management offered.

Keywords: immunohistochemistry; kidney cancer; lung adenocarcinoma; tumor-to-tumor metastasis.

Figure 1

The seed and soil hypothesis: The ability of cancer to metastasize depends on the microenvironment of the target tissue.

Figure 2

The mechanical theory: it is probable that metastasis will happen in areas that correspond to the pattern of blood flow.

Figure 3

PRISMA flowchart of the search process.

Figure 4

(A) Chest CT scan showing in axial section left-sided massive pleural effusion. (B) Incidentally discovered right kidney lesion (arrow) on coronal section of the chest CT scan.

Figure 5

Contrast-enhanced abdominal CT images demonstrates an enhancing mass (arrow) in the right kidney with areas of hemorrhage. (A) Axial section. (B) Coronal section. We obtained ethical approval for the CT scan images used in the study.

Figure 6

(A) The RCC intermingled with an adenocarcinoma morphologically similar to the lung adenocarcinoma (H&E, 20×). (B) CK7 immunoreactivity in the lung ADK. (C) TTF1 positivity in lung ADK. (D) CAIX positivity (immunoperoxidate 20×). We obtained ethical approval for the IHC staining used in the study.