Kidney tumor
Adult renal carcinoma
Type 1 (basophilic) papillary renal cell carcinoma (pRCC)

Author: Nicole K. Andeen, M.D.
Editor: Maria Tretiakova, M.D., Ph.D.

Revised: 13 July 2018, last major update October 2017

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

PubMed Search: Type 1 (basophilic) papillary renal cell carcinoma

Related topics: Papillary type, renal cell carcinoma, type 2, solid growth pattern
Cite this page: Andeen, N.K. Type 1 (basophilic) papillary renal cell carcinoma (pRCC). website. Accessed October 20th, 2018.
Definition / general
  • Type 1 vs type 2 described in 1997 by Delahunt and Elbe (Mod Pathol 1997;10:537); type 1 is more common than type 2
Essential features
  • Composed of small cuboidal cells with scant pale cytoplasm arranged on single layer of papillary cores, tubules and glomeruloid structures
  • Often contains foamy macrophages and psammoma bodies
  • CK7 diffusely positive (Am J Surg Pathol 2014;38:887)
  • Gains in chromosomes 3, 7 and 17 ( > 80%)
  • MET activating mutations or amplifications (N Engl J Med 2016;374:135)
  • Kidney, renal cortex
  • May be multifocal and bilateral
Diagrams / tables

Images hosted on other servers:

NCCN Clinical Practice Guidelines in Oncology

Clinical features
  • In one series of papillary RCCs, ~25% had classical type 1 features, ~25% were type 2 and ~50% had some degree of overlapping features (Am J Surg Pathol 2014;38:887)
Radiology images

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Radiological imaging of kidney tumor

Distinct radiology of papillary RCC, type 1

Prognostic factors
Case reports
Gross description
  • Often well circumscribed with thick capsule
  • Friable with patchy appearance (yellow, grey, brown) and frequent hemorrhage
Microscopic (histologic) description
  • Small cuboidal cells arranged on single layer on papillary cores (Am J Surg Pathol 2014;38:887)
  • Cells are small with uniform, scant pale cytoplasm and round, hyperchromatic nuclei without nucleoli
  • Papillary cores often contain foamy macrophages
  • May have psammoma bodies
  • Lower grade than type 2
  • Grading: ISUP nucleolar grade
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Nicole K. Andeen, M.D. and Maria Tretiakova, M.D., Ph.D.

Papillary cores filled with foamy macrophages

Type 1 pRCC

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Small basophilic
tumor cells
(fig. A)

Small basophilic tumor cells and foam cells

Positive stains
Negative stains
Molecular / cytogenetics description
Differential diagnosis
Board review question #1
Compared to type 2 pRCC, type 1 pRCC generally:

  1. Has more aggressive clinical behavior
  2. Has more CK7 expression and MET activation
  3. Has more diverse chromosomal aberrations
  4. Has more nuclear pleomorphism
Board review answer #1
B. Has more CK7 expression and MET activation