Kidney tumor

Adult renal cell carcinoma - rare


Deputy Editor-in-Chief: Debra L. Zynger, M.D.
Daniel Anderson, M.D., M.B.A.
Maria Tretiakova, M.D., Ph.D.

Last author update: 1 May 2018
Last staff update: 15 August 2022

Copyright: 2003-2022,, Inc.

PubMed Search: Tubulocystic carcinoma kidney

Daniel Anderson, M.D., M.B.A.
Maria Tretiakova, M.D., Ph.D.
Page views in 2021: 7,198
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Cite this page: Anderson D, Tretiakova M. Tubulocystic. website. Accessed August 16th, 2022.
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
ICD coding
  • ICD-10: C64 - malignant neoplasm of kidney, except renal pelvis
  • 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
  • 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. and Daniel Anderson, M.D.

Creamy, soft mass

Partial nephrectomy with tubulocystic 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.
Missing Image

H&E stained sections showing cysts and tubules lined by cuboidal epithelium with scattered hobnailing

Missing Image

IHC images show cytoplasmic CD10, CK7 and EMA positivity

Contributed by Debra Zynger, M.D.

Numerous cysts

Hobnailed lining

Rigid cysts


Small tubules

Fumarate hydratase


Positive stains
Negative 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
Differential diagnosis
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

  1. Few neoplasms progress and metastasize
  2. It consists of a mixture of tubules and micro / macro cysts lined by hobnailed cells
  3. Male predominance
  4. Neoplasm contains stromal hypercellularity (including ovarian type stroma)
  5. Sponge-like or bubble wrap gross appearance
Board review style answer #1
D. Neoplasm contains stromal hypercellularity (including ovarian type stroma). Stromal hypercellularity and ovarian type stroma is a feature of adult cystic nephroma / mixed epithelial and stromal tumor.

Comment Here

Reference: Tubulocystic
Board review style question #2
What is the most accurate way to grossly describe tubulocystic carcinoma?

  1. Large hemorrhagic tumor of renal medulla
  2. Encapsulated multiloculated cystic and solid mass
  3. Honeycomb-like yellow tumor
  4. Well circumscribed mass with spongy or bubblewrap appearance
Board review style answer #2
D. Well circumscribed mass with spongy or bubblewrap appearance. Tubulocystic carcinoma has a very peculiar gross morphology, often compared to bubble wrap, sponge and Swiss cheese.

Comment Here

Reference: Tubulocystic
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