Multilocular Cystic Renal Neoplasm of Low Malignant Potential
This tumor was previously named “multilocular cystic renal cell carcinoma.”
Multicystic tumor with septa containing individual or groups of clear cells with ISUP/WHO 2016 low nucleolar grade (1–2).
This tumor accounts for less than 1% of all renal tumors, usually incidentally discovered.
It occurs in middle-age adults.
There is no difference between male and female.
There is no site predilection.
Partial or radical nephrectomy is the surgical treatment of choice.
To date there are no evidence of recurrence or metastasis.
The tumor consists exclusively of variably sized cysts separated by thin septa and filled with clear, serous, or gelatinous fluid (Fig. 1). Solid, grossly discernible tumor mural nodules are incompatible with the diagnosis.
The cysts are lined by a single layer of neoplastic cells with abundant clear cytoplasm and small nuclei without nucleoli (ISUP/WHO 2016 grade 1 or 2). The septa consist of fibrous tissue with calcification or ossification. An important diagnostic feature is the presence within the fibrous septa of small clusters of tumor cells similar to those lining the cysts. Necrosis, vascular invasion, and sarcomatous transformation are incompatible with this diagnosis.
The neoplastic cells are strong reactive to PAX8 and CAIX, similar to typical clear cell renal cell carcinoma.
Genetic profile VHL mutations have been identified in 25% of tumors.
References and Further Reading
- Tretiakova, M., Mehta, V., Kocherginsky, M., Minor, A., Shen, S.S., Sirintrapun, S.J., Yao, J.L., Alvarado-Cabrero, I., Antic, T., Eggener, S.E., Picken, M.M., & Paner, G.P. (2018) Predominantly cystic clear cell renal cell carcinoma and multilocular cystic renal neoplasm of low malignant potential form a low-grade spectrum. Virchows Archiv, 473, 85–93. [Epub ahead of print].Google Scholar
- Williamson, S. R., Halat, S., Eble, J. N., Grignon, D. J., Lopez-Beltran, A., Montironi, R., Tan, P. H., Wang, M., Zhang, S., Maclennan, G. T., Baldridge, L. A., & Cheng, L. (2012). Multilocular cystic renal cell carcinoma: Similarities and differences in immunoprofile compared with clear cell renal cell carcinoma. The American Journal of Surgical Pathology, 36(10), 1425–1433.CrossRefGoogle Scholar