Eosinophilic Vacuolated Tumor of Kidney: Clinical Perspective of a New Pathologic Emerging Entity

Abstract

The eosinophilic vacuolated tumor (EVT) of the kidney is a newly identified and pathological emerging entity. In this case report, EVT diagnosed due to a partial nephrectomy performed for a suspicious kidney mass in a 47-year-old patient is presented. A review of the literature and this case indicates that EVT, also called high-grade oncocytoma, does not show clinically aggressive behavior. However, in case of clinical suspicion, tumors with this oncocytic morphology should be treated with nephron-sparing treatment methods, considering that they may be hybrid malignancies.

Keywords: eosinophilic; hybrid malignancy; kidney; nephron-sparing treatment; oncocytoma; vacuolated tumor.

Figure 1. Eeosinophilic vacuolated tumor in a 47-year-old man

A-B: Computed tomography transverse and coronal sections showing well-defined round heterogenous enhancement of the left lower pole renal mass (white arrows); C. Coronal contrast-enhanced T1-weighted image shows heterogeneous enhancement in the left lower pole renal mass (white arrow).

Figure 2. A. Tumor shows a solid growth pattern with large thick-walled vessels and entrapped non-neoplastic tubules at the periphery (hematoxylin and eosin x100). B. Tumor cells exhibit voluminous eosinophilic cytoplasm with prominent intracytoplasmic vacuoles. The cells have round nuclei and prominent nucleoli (hematoxylin and eosinx200). C. Tumor cells are positive for CD117 (x100). D. CK7 is negative in tumor cells. Only entrapped non-neoplastic tubules are positive for CK7 (x100).