Clear cell multilocular renal cell carcinoma
Multilocular cystic renal neoplasm of low malignant potential is a low-grade adult renal tumor composed entirely of numerous cysts. The entity was previously known as multilocular cystic renal cell carcinoma, which usually had clear cell morphology, but was redefined in the 2016 WHO classification due to no recurrence or metastasis in patients with these tumors .
Epidemiology
The reported incidence is 1-2% .
Diagnostic consideration
Bosniak classification system of renal cystic lesions is used in the classification of such renal lesions to anticipate the underlying malignant potential. These are usually classified as Bosniak type III lesions which are malignant in approximately 55% cases . It cannot be accurately differentiated from other cystic RCCs clinically or radiologically; however, Bosniak classification system and density measurement (Hounsfield units) in the corticomedullary phase can be helpful in this differentiation. The Hounsfield units (HU) are significantly higher in other cystic RCCs during this phase of the scan and a cut off value of ≥38 HU has a sensitivity of 83% and specificity of 80% .
The epithelial cells lining the cysts and the clusters of clear tumor cells show positivity for epithelium markers like epithelial membrane antigen (EMA), cytokeratin 7 (CK7), and carbonic anhydrase IX (CA-IX), which can be useful in making a more meticulous diagnosis and discriminating it from other cystic renal lesions .
Differential diagnosis
Consider other cystic renal neoplasms in adults, primarily mixed epithelial and stromal tumor and the related cystic nephroma.
Treatment
It is still controversial; however, because of its low malignant potential it is usually treated with partial nephrectomy or nephron-sparing surgery (less trauma and few complications) .
See also
