[990] Extra-Renal Cancer Metastasizing to Primary Renal Neoplasms: A Rare Entity with Important Implications for Clinical Management

Jordan P Reynolds, Mathieu Latour, Jun Zhang, Ximing J Yang, Ming Zhou. Cleveland Clinic, Cleveland, OH; CHUM, Montreal, QC, Canada; Mayo Clinic, Rochester, MN; Northwestern University, Chicago, IL

Background: Extra-renal cancer rarely metastasizes to primary renal neoplasms and may be mistaken for a high grade component of the primary renal neoplasm. Recognition of these metastatic components is critical for proper patient management. Our study describes the clinicopathologic features of these tumors that may aid their recognition.
Design: 9 cases of extra-renal cancer metastatic to primary renal neoplasms were retrieved from the surgical pathology files of authors' institutions. Clinicopathological information and follow-up data were reviewed.
Results: 9 patients (5 male, 4 female) had a mean age of 61.7 (range 47-74) years. 8 underwent nephrectomy, and 1 underwent biopsy. The primary renal tumors were clear cell renal cell carcinoma (CCRCC) in 5 cases and oncocytomas (OC) in 4 cases. The average size of the primary renal neoplasms was 53 (range 17-100) mm. Metastatic cancer included one adenocarcinoma (esophagus), two squamous cell carcinomas (lung), one urothelial carcinoma, three invasive ductal carcinomas (breast), one papillary thyroid carcinoma (PTC), and one diffuse large B cell lymphoma. In all cases, the metastatic tumors were present primarily within the renal tumor vasculature and formed a “second” population of cells that were significantly different from the primary renal neoplasms. 3 cases had multiple tumor foci, and 6 had a solitary metastatic focus. The size of the largest metastatic focus ranged from 4 to 70 mm. Immunohistochemistry staining was necessary to confirm the diagnosis in all cases. The average duration of follow-up is 16 (range 2-72) months. Two patients were dead of the extra-renal cancer, five alive with the extra-renal cancer. Only one patient was alive with CCRCC. One has no evidence of disease (PTC metastatic to CCRCC).
Conclusions: Extra-renal cancers metastatic to primary renal neoplasms are rare but important to recognize. In addition to obtain important clinical history, the presence of a “second” population of cells within renal tumor vasculature should prompt a consideration of metastatic extra-renal cancer. The clinical outcomes in these patients were primarily determined by the extra-renal cancer.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 93, Wednesday Morning


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