Kidney tumor
Adult renal cell carcinoma - rare
Multilocular cystic renal neoplasm of low malignant potential
Topic Completed: 1 July 2016
Minor changes: 8 July 2021
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PubMed search: Multilocular cystic renal cell carcinoma kidney
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Clinical features | Diagnosis | Radiology description | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Andeen NK, Tretiakova M. Multilocular cystic renal neoplasm of low malignant potential. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneytumormcrnlow.html. Accessed August 4th, 2021.
Definition / general
- "Neoplasm composed entirely of numerous cysts, the septa of which contain individual or groups of clear cells without expansile growth" (WHO 2016)
Essential features
- Multicystic; no expansile growth
- Clear cells with low grade nuclei (ISUP grade 1 or 2)
- No recurrence or metastases when diagnosed on strict criteria
- Distinguish from regressing clear cell renal cell carcinoma (ccRCC) with cystic degeneration, which often has cysts filled with hemorrhage, necrosis and hemosiderin deposits; may have extensive hyalinization and often has areas of expansile growth of neoplastic cells
Terminology
- 2016 WHO separates this neoplasm of low malignant potential from cystic renal cell carcinomas which have some overlapping morphologic features
- Use of "multilocular cystic renal cell carcinoma" is considered obsolete (WHO 2016); some literature references in this topic use the older terminology
Epidemiology
- Accounts for less than 1% of all renal tumors
- Middle age adults
- Male:female ratio ranges from 1.2:1 to 2.1:1
Sites
- Kidney only
Clinical features
- 90% are discovered incidentally, on radiology for other purposes
- Excellent prognosis with no recurrences or metastases in multiple case series when diagnosed on strict criteria (Am J Surg Pathol 2013;37:1469, Am J Clin Pathol 2006;125:217)
Diagnosis
- There are no current guidelines or definitive evidence regarding the question of whether complete histologic examination is required for diagnosis (Am J Surg Pathol 2013;37:1469)
Radiology description
Case reports
- 30 year old man with 2 year history of intermittent right flank pain and gross hematuria (Can Urol Assoc J 2014;8:E545)
- 55 year old man with pain in left lumbar region and hematuria since 2 months (J Lab Physicians 2014;6:50)
Treatment
- Resection, preferably nephron sparing surgery
Gross description
- Usually unilateral and less than 5 cm
- Variably sized cysts filled with clear, serous or gelatinous fluid; much less commonly hemorrhagic debris
- No mural nodules
Gross images
Images hosted on other servers:
Large multi-cystic mass
Cysts filled with gelatinous material
Microscopic (histologic) description
- Thin fibrous septae with clear cells lining the septa or in small clusters
- Low grade nuclei without nucleoli (ISUP grade 1 - 2)
- Cyst lining may be denuded and bland clear cells in septa may be mistaken for lymphocytes; look for vascularity
- No expansile growth of clear tumor cells / solid nodules
- No necrosis, vascular invasion or sarcomatoid change
- In rare cases, lining of cysts may show multilayering, cells with granular cytoplasm and small intracystic papillations
- Septa may contain calcification or ossification
Microscopic (histologic) images
Contributed by Maria Tretiakova, M.D., Ph.D.
Composed of variably sized cysts with thin septae lined by a layer of clear cells with low nuclear grade; no expansile nodules
Images hosted on other servers:
Various images
Negative stains
- AMACR negative in 80% (Am J Surg Pathol 2012;36:1425)
Molecular / cytogenetics description
- Genetically related to clear cell renal cell carcinoma, with 74% of cases demonstrating 3p loss and VHL mutations identified in 25% (Mod Pathol 2011;24:571, Mod Pathol 2010;23:931)
Differential diagnosis
- Benign renal cortical cyst: usually unilocular and lacks mural clear cell clusters
- Clear cell renal cell carcinoma (ccRCC) with cystic and / or regressive changes: ccRCC often has cysts filled with hemorrhage, necrosis and hemosiderin deposits; may have extensive hyalinization and often has areas of expansile growth of neoplastic cells
- Cystic nephroma: variably sized cysts with thin fibrous septae lined by bland non clear cells; stromal cells positive for ER, PR and CD10; epithelial cyst lining positive for HMWCK, CK19 and AMACR (Int J Surg Pathol 2015;23:238)
- MiT family tumors: usually high grade tumors with at least focal solid areas, psammoma bodies, TFE3 nuclear positivity (Int J Surg Pathol 2007;15:199)
- Tubulocystic carcinoma: is usually composed of regular, sponge-like small to medium sized tubules which are occasionally cystically dilated; cells lining spaces are enlarged, oncocytic with hobnailing and prominent nucleoli (nucleolar grade 3); intervening septa is hypocellular and fibrotic; expresses CD10, AMACR and sometimes CK7 and HMWCK with less than half expressing CAIX (Am J Surg Pathol 2013;37:1469)
Additional references
