Kidney tumor

Benign / borderline adult tumors

Papillary adenoma



Last author update: 14 May 2024
Last staff update: 14 May 2024

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PubMed Search: Papillary adenoma kidney

Vincent Francis Castillo, M.D.
Rola Saleeb, M.D., Ph.D.
Page views in 2024 to date: 8,640
Cite this page: Castillo VF, Saleeb R. Papillary adenoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneytumorrenalcortadenoma.html. Accessed July 13th, 2024.
Definition / general
  • Benign unencapsulated renal epithelial neoplasm characterized by papillary, tubular or tubulopapillary architecture with low grade nuclei and a diameter of ≤ 15 mm
Essential features
  • Benign papillary or tubulopapillary, low nuclear grade lesions of the kidney, similar in morphology to classic papillary renal cell carcinoma (PRCC); however, they lack fibrous capsules and are ≤ 15 mm
  • Prevalent in damaged and injured kidneys
    • Could be related to a progenitor / stem cell-like renal tubular cell population that increases upon kidney damage
  • Postulated to be precursor lesions to PRCC
    • However, the prevalence of adenoma is much higher than of carcinoma, indicating that many of them do not progress
Terminology
  • Tubulopapillary adenoma
  • Renal adenoma (not recommended)
ICD coding
  • ICD-O: 8260/0 - papillary adenoma, NOS
  • ICD-11: 2F35 & XH09B0 - benign neoplasm of urinary organs & papillary adenoma, NOS
Epidemiology
Sites
  • Renal cortex
Pathophysiology
Etiology
  • Unknown, possibly secondary to renal injury as chronic medical renal diseases, pyelonephritis or nearby mass tumor effect (Am J Pathol 2019;189:2046)
Clinical features
Diagnosis
  • Imaging: usually computed tomography (CT) scan, ≤ 15 mm, often not seen
  • Biopsy or resection
    • Diagnosis on needle biopsy should be made with caution as capsule and nuclear grade heterogeneity may not be visualized
Radiology description
  • CT / magnetic resonance imaging (MRI): ≤ 15 mm in size
  • No specific imaging findings; may be difficult to distinguish from other renal lesions
Radiology images

Images hosted on other servers:
MRI of renal adenomatosis

MRI of renal adenomatosis

Prognostic factors
  • Benign lesions thought to be precursors of PRCC (Hum Pathol 2007;38:239, Mod Pathol 2003;16:1053)
    • However, the incidence of PRCC is much lower than papillary adenoma, indicating that not all cases have the potential to progress to PRCC (Am J Pathol 2019;189:2046)
  • Size criterion has been changed from 5 mm to 15 mm based on data that these lesions have no capacity to metastasize (Eur Urol 2011;60:983)
    • Change allows for increased acceptance of donor kidneys for transplantation, in which kidneys with papillary lesions ≤ 15 mm would not be rejected (Ann Transplant 2014:19:362)
Case reports
Treatment
  • Treatment is based on the presenting tumor or condition
  • Considered benign; does not on its own require treatment
Gross description
  • Usually subcapsular
  • Spherical or wedge shaped, grayish white to yellow (Am J Surg Pathol 2019;43:277)
  • Smaller lesions may not be visible
  • May be multiple (renal adenomatosis)
Gross images

AFIP images
1.5 cm subcapsular tumor

1.5 cm subcapsular tumor

Microscopic (histologic) description
  • Papillary, tubular or tubulopapillary architecture
  • No fibrous capsule; in direct contact to adjacent renal parenchyma
  • Lined by cuboidal cells with scant, pale cytoplasm with low nuclear grade (WHO / International Society of Urological Pathology [ISUP] grade 1 - 2) (similar to classic pattern of PRCC)
    • Papillary adenomas are benign lesions and are not graded
    • Tumors with high grade nuclei should not be diagnosed as papillary adenoma
  • Some lesions show cytoplasmic clearing with fine granularity similar to what is occasionally seen in PRCC
    • Lesions diagnostic of clear cell papillary renal cell tumor should not be considered as papillary adenoma
  • Absent to rare mitosis
  • Foamy macrophages and psammomatous calcifications may be present (Am J Surg Pathol 2019;43:277)
Microscopic (histologic) images

Contributed by Rola Saleeb, M.D., Ph.D. and Vincent Francis Castillo, M.D.
No fibrous capsule

No fibrous capsule

Tubulopapillary architecture

Tubulopapillary architecture

Subcapsular location

Subcapsular location

Small unencapsulated tumor

Small unencapsulated tumor

Cytoplasmic clearing

Cytoplasmic clearing


Foamy histocytes

Foamy histocytes

Hemosiderin pigments

Hemosiderin pigments

Papillary adenoma

Basophilic scant cytoplasm

CK7

CK7

Cytology description
Positive stains
Negative stains
Molecular / cytogenetics description
Molecular / cytogenetics images

Images hosted on other servers:
Chromosome 12 trisomy

Chromosome 12 trisomy

Sample pathology report
  • Kidney, left, partial nephrectomy:
    • Papillary adenoma, 1.2 cm

  • Kidney, right, needle core biopsy:
    • Low grade papillary renal lesion (see comment)
    • Comment: The differential diagnosis includes papillary adenoma and papillary renal cell carcinoma. The clinical history is noted regarding the 0.6 cm size of the lesion. Clinical correlation is advised as to the size of the lesion by imaging. A lesion ≤ 1.5 cm would be consistent with a papillary adenoma, while a lesion > 1.5 cm would be classified as a papillary renal cell carcinoma.
Differential diagnosis
Board review style question #1

A 38 year old woman with recurrent pyelonephritis was found to have a 1 cm left renal mass on imaging. A biopsy of the lesion was performed and showed the morphology above. Which of the following is the correct diagnosis and WHO / ISUP grade?

  1. Papillary adenoma, not graded
  2. Papillary adenoma WHO / ISUP grade 2
  3. Papillary renal cell carcinoma WHO / ISUP grade 1
  4. Papillary renal cell carcinoma WHO / ISUP grade 2
Board review style answer #1
A. Papillary adenoma, not graded. Papillary adenomas are low grade lesions by morphology; however, they are considered benign and are not graded as per the current guidelines. Answer B is incorrect because grading is not recommended for papillary adenoma. Answers C and D are incorrect because to diagnose papillary renal cell carcinoma, the tumor size should be > 1.5 cm.

Comment Here

Reference: Papillary adenoma
Board review style question #2
What are the chromosomal aberrations reported in papillary adenoma lesions?

  1. Multiple chromosomal gains and losses
  2. Trisomies of 7 and 17 only
  3. Trisomies of 7, 17 and loss of Y and less frequently gains in chromosomes 12, 16 and 20
  4. Trisomies of 7, 17 and loss of Y as well as deletions of the short arm of chromosome 3
Board review style answer #2
C. Trisomies of 7, 17 and loss of Y and less frequently gains in chromosomes 12, 16 and 20. Papillary adenomas show chromosomal aberrations similar to low grade papillary renal cell carcinoma (PRCC), which include trisomies of chromosomes 7 and 17, loss of Y and occasional gains in 12, 16 and 20. Answer B is incorrect because other chromosomal aberrations have also been reported in papillary adenoma. Answer D is incorrect because chromosome 3p deletions are common in clear cell RCC. Answer A is incorrect because multiple chromosomal alterations are typically seen in high grade PRCC.

Comment Here

Reference: Papillary adenoma
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