Mixed epithelial and stromal tumor of the kidney: an analysis of multidetector computed tomography manifestations and clinicopathologic findings

OBJECTIVES

To explore the features of mixed epithelial and stromal tumor of kidney (MESTK) on the images of multidetector computed tomography with clinical manifestations and pathological findings as a reference.

METHODS

On the basis of a blind retrospective review, we analyzed the images of 6 cases of MESTK on multidetector computed tomography and compared them with pathological results postoperatively. Two reviewers were asked to classify the tumors according to the Bosniak classification. We also combined them with clinical data, pathological findings, and reviewed literatures.

RESULTS

All tumors were single, unilateral, and well circumscribed with a clear delineation from renal parenchyma. Five were round or oval, whereas 1 was irregularly shaped. One tumor processed to renal pelvis, 1 protruded from the cortex, and 4 large masses processed to both the cortex and the pelvis. In 6 cases, all MESTKs consisted of an irregular mixture of solid and cystic areas. The cysts were multilocular with smooth walls and low-density cystic liquid. No mural nodules were observed. Five tumors were diagnosed as Bosniak III, and 1 as Bosniak IV. Solid parts presented a mild-to-moderate enhancement and delayed enhancement without any enhancement of the cystic ones.

CONCLUSIONS

Radiologists should consider the possibility of MESTK when they find that the tumor is a single solid or a cystic solid mass, especially in a female patient, and that the solid components present a mild-to-moderate enhancement during the corticomedullary phase and delayed enhancement, but the definite diagnosis depends on pathology.