The aim of this report is to present a case of MCRCC and emphasize the importance of the preoperative radiologic evaluation and immunohistochemical staining confirmation to obtain an accurate diagnosis.
With these findings, the definitive pathological diagnosis changed from cystic nephroma to MCRCC with a Fuhrman grade of 1, with surgical margins negative for neoplasia.
Benign renal masses can also be part of the differential diagnosis of MCRCC. This includes mixed epithelial and stromal tumors of the kidney, cystic nephroma, Multilocular cysts, and renal abscess .
The diagnostic evaluation of patients with MCRCC is troublesome before surgery due to the nonspecific radiological findings of this pathology.
According to these findings, some studies have tried to differentiate between MCRCC of other cystic RCC.
In our case the reported HU in the corticomedullary phase were 37 HU, thus supporting the fact of facing a MCRCC.
 tried to improve the accuracy of preoperative diagnosis between CN and MCRCC. They observed that shallow lobulation, protruding to the renal sinus, thin walls, and partitions without nodules, favored CN and net growth in the cortical and nephrographic phase, thick walls, nodules, and higher enhancement after contrast media administration indicated a higher possibility of MCRCC.
Histologically, there are different features that could help distinguish cystic nephroma from MCRCC. In CN, there are focally distributed clear cells in the surface of the septa, hobnail epithelium, ovarian-like stroma, and mature tubules in the septa, whereas evident solid areas in cystic mass or extensile nodules of clear cells favor MCRCC [12, 13].
 compared 19 cases of MCRCC versus other cystic kidney lesions and 22 benign simple cortical cysts as controls.
Therefore we can assume that useful immunohistochemical staining for EMA, CK7, and CA-IX may be helpful in establishing a more accurate diagnosis and differentiating other cystic lesions from MCRCC as we saw in our case.
Concerning the best modality of treatment for these patients, literature is still controversial but there may be some preference to treat MCRCC by partial nephrectomy due to its low aggressive potential.
In one of the larger series reporting treatment and outcomes, they treated 76 patients with MCRCC; 18 underwent radical open nephrectomy, 18 laparoscopic radical nephrectomy, 22 open partial nephrectomy, and 18 laparoscopic partial nephrectomy.