Molecular Characterization of Metastatic Oncocytoma With Exceptional Response to Treatment: A Case Report

Abstract

Comprehensive molecular characterization and effective therapy in a rare case of metastatic renal oncocytoma.

Figure 1:. Pre- and post-operative imaging of metastatic renal oncocytoma in a 29-year old female.

(a) MRI images showing both the primary right renal mass (dashed arrow) and multiple hepatic metastatic lesions (solid arrows). (b) Pre-operative 99mTc-sestamibi single-photon emission CT scan showing centrally photopenic right renal mass with increased peripheral rim uptake along with numerous hepatic enhancing lesions (solid arrows). Left renal uptake also noted (dashed arrow) despite lack of left renal lesions on CT or MRI. (c) 4 month post-operative MRI showing residual hepatic lesions (solid arrows) that were subsequently ablated by interventional radiology with large hepatic defects from prior surgical resection (dashed arrows).

Figure 2:. Representative pathology images for primary and metastatic lesions.

H&E staining for the primary and metastatic lesions show similar histology. c-KIT and cytokeratin 7 immunohistochemistry staining shows findings consistent with renal oncocytoma and no features of chromophobe RCC. KI67 proliferative index measures were < 5% suggesting a non-aggressive profile.

Figure 3:. RNAseq analysis comparing patients oncocytomas to other sporadic oncocytomas

A) PCA analysis of RNAseq data comparing normal kidney samples (n=8, dark green, normal kidney from case patient (light green), sporadic oncocytomas from 10 patients (n=21, purple), and primary tumor (PT) and metastases (PM1/2) form the case patient (n=3, red). All oncocytomas clustered away from the normal kidneys. The sporadic oncocytomas clustered into two specific groups, with the upper group correlating with increased CCND1 expression. The primary and metastatic samples from the case patient clustered very closely together and apart from the other oncocytomas. B-D) RNAseq data for normal kidney samples (n=8, dark green, normal kidney from case patient (light green), sporadic oncocytomas from 10 patients (n=21, purple), and primary tumor and metastases from the case patient (n=3, red). * <0.05, ** <0.01, ***<0.001