Kidney tumor
Adult renal cell carcinoma - rare
Tubulocystic
Deputy Editor-in-Chief: Debra L. Zynger, M.D.
Topic Completed: 1 May 2018
Minor changes: 27 October 2020
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PubMed Search: Tubulocystic carcinoma kidney
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Pathophysiology | Clinical features | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Electron microscopy images | Molecular / cytogenetics description | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Anderson D, Tretiakova M. Tubulocystic. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneytumormalignanttubulocystic.html. Accessed January 25th, 2021.
Definition / general
- Renal epithelial neoplasm composed predominately of tubules and cysts lined by a single layer of cells with prominent nucleoli (ISUP grade 3) and abundant eosinophilic cytoplasm (Eur Urol 2016;70:93)
- Relatively indolent with < 10% cases showing disease progression, local recurrence or metastasis to bone, liver and lymph nodes (Eur Urol 2016;70:93)
- Recognized by the 2016 WHO classification
Essential features
- Well circumscribed tumor with spongy bubble wrap appearance
- Strong male predominance
- Pure cystic and tubular architecture; no solid areas
- Single layer of flat, cuboidal or hobnailed eosinophilic cells along fibrotic septa
Terminology
- Originally named Bellinien epithelioma or collecting duct carcinoma by Pierre Masson in the 1950s (Am J Surg Pathol 2016;40:1457)
- Low grade collecting duct carcinoma (McLennan) (Urology 1997;50:679)
- Termed tubulocystic renal cell carcinoma and considered a distinct entity since 2009 (Am J Surg Pathol 2008;32:177)
ICD coding
- ICD-10: C64 - malignant neoplasm of kidney, except renal pelvis
Epidemiology
- Rare (< 100 cases)
- Mean age 54 years
- 7:1 male:female predominance (Am J Surg Pathol 2009;33:384)
Pathophysiology
- Histogenesis remains unclear; cells have some features of proximal nephron differentiation and others relate to distal nephron (Can Urol Assoc J 2015;9:E654)
Clinical features
- Often an incidental finding with ~90% low stage
- Less commonly presents with abdominal pain, distention, hematuria, weight loss
- Prognosis is typically excellent with rare recurrences, distant metastases or death from disease
Case reports
- 22 year old woman with bone metastasis (J Korean Soc Radiol 2011;65:285)
- 34 year old man with a 1.4 cm mass (Case of the Month #484)
- 43 year old man with multiple focal clear cell characteristics (J Carcinog Mutagen 2015;6:213)
- 45 year old man initially misdiagnosed with a Bosniak type II renal cyst (Rev Urol. 2016;18:118)
- 47 year old man and 66 year old man with poorly differentiated foci (Int J Clin Exp Pathol 2015;8:11124)
- 62 year old man with bilateral tumors in diabetic end stage renal disease (Rare Tumors 2013;5:e57)
- 65 year old man with a large cystic tumor (Can Urol Assoc J 2015;9:E654)
Treatment
- Radical or partial nephrectomy depending on tumor size and location in the kidney
- No established targeted therapy in metastases but a few case reports suggest a partial response to sunitinib (a tyrosine kinase inhibitor) and everolimus (a mammalian target of rapamycin [mTOR] inhibitor) (Rev Urol 2016;18:118)
Gross description
- Well circumscribed but not encapsulated
- Cut surface that is grey white with multilocular cystic spaces resembling a sponge, Swiss cheese or bubble wrap appearance
- Mean size 4 cm (range 0.2 - 17 cm)
- No hemorrhage or necrosis
Gross images
Contributed by Debra Zynger, M.D.
Creamy, soft mass
Contributed by Daniel Anderson, M.D.
Partial nephrectomy with tubulocytic RCC
Images hosted on other servers:
Brown, fleshy tumour with numerous cysts
Tubulocystic renal cell carcinoma
Microscopic (histologic) description
- Mixture of closely packed tubules and variably sized cysts with overall low grade morphology (Urology 1997;50:679)
- Cysts are separated by fibrous septa; no desmoplasia or cellular stroma
- Tubules and cysts are lined by a single layer of flattened, cuboidal or columnar cells; hobnailing may be present with modest to abundant amounts of eosinophilic cytoplasm resembling oncocytoma cells
- Uniform round nuclei with distinct nucleoli (ISUP grade 3)
- Association with papillary cell neoplasms is not uncommon
- Minimal mitotic activity and atypia, very rare necrosis
Microscopic (histologic) images
Contributed by Maria Tretiakova, M.D., Ph.D.
Tubules and variably sized cysts lined by cuboidal epithelium
Hobnailing and distinct nucleoli
Contributed by Sabrina Sopha, M.D.
H&E stained sections showing cysts and tubules lined by cuboidal epithelium with scattered hobnailing
IHC images show cytoplasmic CD10, CK7 and EMA positivity
Contributed by Debra Zynger, M.D.
Numerous cysts
Hobnailed lining
Rigid cysts
Nucleoli
Small tubules
Fumarate hydratase
PR
Positive stains
Electron microscopy description
- Short microvilli with brush border organization
- Ultrastuctural features resembling both cells of the proximal tubules and collecting ducts
Electron microscopy images
Images hosted on other servers:
Type I and type II cells
Molecular / cytogenetics description
- Distinct molecular signature from other carcinomas (J Mol Diagn 2018;20:34)
- Frequent gain of chromosome 7 and 17, loss of Y, similar to papillary renal cell carcinoma Am J Surg Pathol 2009;33:1840, Am J Surg Pathol 2008;32:177)
- Targeted next generation sequencing identified mutations in 14 different genes, most frequently (60% of tubulocystic carcinoma cases) in ABL1 and PDFGRA genes (J Mol Diagn 2018;20:34)
Differential diagnosis
- Adult cystic nephroma (mixed epithelial and stroma tumor) and pediatric cystic nephroma: in adults, predominance in women; biphasic tumors with epithelial and stromal components; multilocular cysts are lined by attenuated cells with inconspicuous nucleoli; nonepithelial component could be very prominent with hyalinization, fibrosis and ovarian type cellular stroma; overlapping expression profile
- Hereditary Leiomyomatosis and Renal Cell Carcinoma (HLRCC) syndrome associated renal cancer with tubulocystic carcinoma-like areas: high grade tumors with solid, papillary and glandular architecture; characteristic large cytomegalovirus-like nucleoli with perinuclear halos; FH gene mutations; fumarate hydratase negative and 2 succino cysteine positive (Am J Surg Pathol 2016;40:1457)
- Multilocular cystic clear cell renal neoplasm of low malignant potential: cysts lined by clear cells with low grade nuclei (ISUP grade 1 - 2); CAIX positive
- Mucinous tubular and spindle cell neoplasm: predominantly women, typically long tubular profiles or cordlike growth pattern of uniform, low cuboidal cells with eosinophilic, focally vacuolated cytoplasm and spindling; stroma is myxoid and bubbly with abundant extracellular mucin
Board review style question #1
The neoplasm shown in the picture is a recently recognized distinct entity of the kidney that has all the following features, except:
- Few neoplasms progress and metastasize
- It consists of a mixture of tubules and micro/macro cysts lined by hobnailed cells
- Male predominance
- Neoplasm contains stromal hypercellularity (including ovarian type stroma)
- Sponge-like or bubble wrap gross appearance
Board review style answer #1
D. Stromal hypercellularity and ovarian type stroma is a feature of adult cystic nephroma / mixed epithelial and stromal tumor.
Reference: Kidney tumor - Tubulocystic renal cell carcinoma
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Reference: Kidney tumor - Tubulocystic renal cell carcinoma
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Board review style question #2
What is the most accurate way to grossly describe tubulocystic carcinoma?
A. Large hemorrhagic tumor of renal medulla
B. Encapsulated multiloculated cystic and solid mass
C. Honeycomb-like yellow tumor
D. Well circumscribed mass with spongy or bubblewrap appearance
A. Large hemorrhagic tumor of renal medulla
B. Encapsulated multiloculated cystic and solid mass
C. Honeycomb-like yellow tumor
D. Well circumscribed mass with spongy or bubblewrap appearance
Board review style answer #2
D. Tubulocystic carcinoma has a very peculiar gross morphology, often compared to bubble wrap, sponge and Swiss cheese.
Reference: Kidney tumor - Tubulocystic renal cell carcinoma
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Reference: Kidney tumor - Tubulocystic renal cell carcinoma
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