Collision Tumor of the Kidney Composed of Clear Cell Renal Cell Carcinoma and Papillary Renal Cell Carcinoma-A Report of a Unique Case

• Main Author: Vladimír Bartoš
• Format: Article
• Language: English
• Published: Amber Publication 2018-08-01
• Series: Journal of Research in Medical and Dental Science
• Subjects: Collision tumor; Renal cell carcinoma; Histologic subtypes
• Online Access: https://www.jrmds.in/articles/collision-tumor-of-the-kidney-composed-of-clear-cell-renal-cell-carcinoma-and-papillary-renal-cell-carcinomaa-report-of-.pdf

A collision tumor is characterized by the coexistence of two adjacent but different tumor types with no histological admixture, forming a single lesion. The author describes a 70-year-old man, who was found to have a solitary tumor in the left kidney. Histologically, it had two distinct yet intimately associated cancer components. The first one was a conventional clear cell RCC, while the second component represented a papillary RCC. The border between them was conspicious and corresponding cell populations did not mix together. Immunohistochemically, papillary RCC component strongly expresses cytokeratin 7 and alpha-methylacyl-CoA racemase. The final diagnosis was a collision tumor consisted of clear cell RCC and papillary RCC. Three years after surgery the patient felt well without a locoregional recurrence or distant metastasis. A collision tumor of the kidney composed of two distinct RCC subtypes is very rare finding. At the biopsy examination, a careful inspection of entire tumor lesion with precise section sampling from all areas that look grossly different is important to unveil such possible association. Further clinical outcome may be questionable, because different RCC subtypes possess distinct biological behaviour. As a general rule, a prognosis is usually determined by higher-grade cancer component.