Kidney tumor
Adult renal cell carcinoma
Tubulocystic carcinoma

Author: Daniel Anderson, M.D. MBA
Editor: Maria Tretiakova, M.D., Ph.D.

Revised: 6 June 2018, last major update May 2018

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Tubulocystic carcinoma kidney

Cite this page: Anderson, D. Tubulocystic carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneytumormalignanttubulocystic.html. Accessed June 25th, 2018.
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
ICD-10 coding
  • C64-: malignant neoplasm of kidney, except renal pelvis
Epidemiology
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
Gross description
  • Well circumscribed but not encapsulated
  • On cut surface, grey white with multilocular cystic spaces resembling a sponge, Swiss cheese or bubble wrap appearance
  • Mean size 4 cm (range 0.2 - 17 cm)
  • Without hemorrhage or necrosis
Gross images

Images hosted on PathOut server:

Contributed by
Daniel Anderson, M.D.

Partial nephrectomy tubulocytic carcinoma


Case of the Week
#51

Cystic lesion



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

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Images hosted on PathOut server:

Contributed by Maria Tretiakova, M.D., Ph.D.

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Images contributed by Sabrina Sopha, M.D.
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Immunostains of a tubulocystic carcinoma of the kidney




Various images


PAS

CK7

CD10

Ki67



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Low magnification

Cuboidal cells

Tubules

High magnification

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
Molecular / cytogenetics description
Differential diagnosis
Board review question #1
Tubulocystic carcinoma is a recently recognized distinct entity 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 answer #1
D. Stromal hypercellularity and ovarian type stroma is a feature of adult cystic nephroma / mixed epithelial and stromal tumor.