[1030] Renal Cell Carcinoma with Rhabdoid Features: Clinicopathologic Features and Molecular Profiles

CW Yoo, JY Ro, K Alvarez, GM Quiroga-Garza, SS Shen, LD Truong, AG Ayala, FA Monzon. The Methodist Hospital, Houston, TX; Weill Cornell Medical College, New York, NY

Background: Tumor cells with rhabdoid morphology are often associated with high-grade renal cell carcinoma (RCC). It has been suggested that rhabdoid cells represent a subclonal proliferation of RCC with a dedifferentiated morphology. If this is true, rhabdoid cells should show unique genomic aberrations when compared to non-rhabdoid areas. In this study, we utilized virtual karyotyping to evaluate the genomic profiles of the rabdoid tumor cells in clear cell RCCs and compare them to those of the non-rhabdoid areas from the same tumors.
Design: Nine cases of clear cell RCC with rhabdoid features were identified. DNA extraction from paraffin-embedded tissues was performed from rhabdoid and non-rhabdoid areas of the tumors. All cases were analyzed with virtual-karyotyping using the Affymetrix GeneChip 250K Nsp mapping arrays. Three cases yielded results for both rhabdoid and clear cell components, and 3 cases only gave results on the rhabdoid component and 3 cases failed analysis. Chromosome copy number data were reviewed and compared between rhabdoid and non-rhabdoid cells.
Results: The average age of patients was 57.4 years (range, 38-75 years) and male to female ratio was 3:1. Rhabdoid cells were present in 3% to 60% of the entire tumor. Non-rhabdoid tumor cells were clear cell type. Average size of the tumor was 8.4 cm (range, 4.0-11.6 cm). All tumor showed necrosis, and had Fuhrman nuclear grade 3 or 4 and all were stages III or IV. Three patients had distant metastasis (bone, lung and heart) Virtual karyotyping data identified loss of 3p in all cases, consistent with clear cell RCC. All but one case showed chromosomal abnormalities commonly found in high-grade RCC tumors (such as loss of 9p and 14q), while one tumor showed 3p loss as the only abnormality. In all three cases in which a rhabdoid and a non-rhabdoid sample were analyzed, the chromosomal profiles were identical. No specific chromosomal abnormalities were seen that were common among tumors with rhabdoid morphology.
Conclusions: Clinicopathologic characteristics of our eight cases are similar to those reported in the literature. Virtual karyotyping identified chromosomal profiles often found in high-grade RCC tumors. However, we did not identify any specific chromosomal changes associated with rhabdoid tumor cells. These results suggest that rhabdoid morphology does not originate from a genomic event involving large chromosomal gains or losses.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 164, Tuesday Morning

 

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