Nephrogenic adenoma

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Nephrogenic adenoma
Diagnosis in short

Nephrogenic adenoma. H&E stain.

Synonyms mesonephric adenoma, nephrogenic metaplasia

LM classically tubular structures with a microcystic appearance lined by hobnailed cells +/-thick eosinophilic basement membrane; may have tubulocystic, polypoid, papillary or fibromyxoid architecture; usually associated with chronic inflammation
LM DDx urothelial carcinoma microcystic and nested variants, prostatic adenocarcinoma, clear cell adenocarcinoma (clear cell adenocarcinoma of the urethra, clear cell carcinoma of the urinary bladder, metastatic clear cell adenocarcinoma)
IHC CK7 +ve, PAX8 +ve, p53 -ve, CEA -ve, Ki-67 low (<5%)
Site urothelium - usu. urinary bladder

Prevalence uncommon
Endoscopy occasionally a papillary-like mass or flat velvety lesion
Prognosis benign
Clin. DDx no treatment necessary (?)

Nephrogenic adenoma, also known as mesonephric adenoma,[1] and nephrogenic metaplasia, is a rare lesion that is classically in the urinary bladder and can mimic adenocarcinoma.

It should not be confused with metanephric adenoma.

General

Features:[2]

  • Benign.
    • May mimic adenocarcinoma!
  • Classic location is the urinary bladder.
    • Also reported in ureter and prostatic urethra.
  • It is thought to result from displacement of renal tubular cells, as this entity in renal transplant recipients is graft derived.[3]

Gross

Features:

  • Usually an incidental finding only seen on microscopy.
  • May manifest as:
    • A papillary-like mass.[4]
    • A flat velvety lesion with an irregular border.[4]

Microscopic

Features:[2]

  • Tubular structures - the classic morphology. †
    • Lined by a single cell layer - classically hobnailed. ‡
    • +/-Thick eosinophilic basement membrane.
    • Typically microcystic appearance.
  • Usually associated with chronic inflammation.

Notes:

  • May mimic vascular/lymphatic channels - can be sorted-out with IHC.
  • † May be tubulocystic, polypoid, papillary or fibromyxoid.[5]
  • ‡ May be flat.[5]
  • Should not have necrosis or mitoses.

DDx:

Images

www:

IHC

Features:[9]

Others:[2]

  • p53 -ve.
  • CEA -ve.
  • Ki-67 low (<5%).
  • MUC1 +ve.
    • Marks distal renal tubule.[11]
  • PSA -ve.[12]
  • PSAP -ve.[12]
  • CD34 -ve.[13] (???)
  • p63 -ve (0/32 cases[14] ).
  • CK20 -ve usually (6 +ve of 32 cases[14]).
  • CK34betaE12 -ve usually (8+ve of 32 cases[14]).

Sign out

PROSTATE TISSUE, TRANSURETHRAL RESECTION OF THE PROSTATE (TURP):
- BENIGN PROSTATE TISSUE WITH GLANDULAR AND STROMAL PROLIFERATION.
- UROTHELIAL MUCOSA WITH A MILD LYMPHOCYTIC INFILTRATE AND CHANGES CONSISTENT
  WITH CYSTITIS CYSTICA.
- BENIGN CALCIFICATIONS.
- NEPHROGENIC METAPLASIA (MESONEPHRIC ADENOMA), SEE COMMENT.
- NEGATIVE FOR MALIGNANCY.

COMMENT:
Nephrogenic metaplasia is a benign finding.  It is confirmed with immunostaining 
(POSITIVE for CK7, PAX8; NEGATIVE for AMACR, CK34betaE12 (very focal staining)).

See also

References

  1. Singh, KJ. (Jan 2011). "Mesonephric adenoma in remnant ureteric stump: A rare entity.". Indian J Urol 27 (1): 140-1. doi:10.4103/0970-1591.78414. PMID 21716880.
  2. 2.0 2.1 2.2 Gokaslan, ST.; Krueger, JE.; Albores-Saavedra, J. (Jul 2002). "Symptomatic nephrogenic metaplasia of ureter: a morphologic and immunohistochemical study of four cases.". Mod Pathol 15 (7): 765-70. doi:10.1097/01.MP.0000019578.51568.24. PMID 12118115. http://www.nature.com/modpathol/journal/v15/n7/full/3880603a.html.
  3. Mazal, PR.; Schaufler, R.; Altenhuber-Müller, R.; Haitel, A.; Watschinger, B.; Kratzik, C.; Krupitza, G.; Regele, H. et al. (Aug 2002). "Derivation of nephrogenic adenomas from renal tubular cells in kidney-transplant recipients.". N Engl J Med 347 (9): 653-9. doi:10.1056/NEJMoa013413. PMID 12200552.
  4. 4.0 4.1 Amin, Mahul B. (2010). Diagnostic Pathology: Genitourinary (1st ed.). Amirsys. pp. 2-27. ISBN 978-1931884280.
  5. 5.0 5.1 Piña-Oviedo, S.; Shen, SS.; Truong, LD.; Ayala, AG.; Ro, JY. (Jun 2013). "Flat pattern of nephrogenic adenoma: previously unrecognized pattern unveiled using PAX2 and PAX8 immunohistochemistry.". Mod Pathol 26 (6): 792-8. doi:10.1038/modpathol.2012.239. PMID 23328975.
  6. Doddamani, D.; Ansari, MS.; Gupta, NP.; Aron, M.; Singh, I.; Datta Gupta, S. (2002). "Mesonephroid adenocarcinoma of the bladder and urethra: a case report.". Int Urogynecol J Pelvic Floor Dysfunct 13 (1): 47-9. PMID 11999207.
  7. Abbas, M.; Kramer, MW.; Wolters, M.; Herrman, TR.; Becker, JU.; Kreipe, HH. (Feb 2013). "Adenocarcinoma of the urinary bladder, mesonephroid type: a rare case.". Rare Tumors 5 (1): e3. doi:10.4081/rt.2013.e3. PMID 23772302.
  8. Kunju, LP. (Oct 2010). "Nephrogenic adenoma: report of a case and review of morphologic mimics.". Arch Pathol Lab Med 134 (10): 1455-9. doi:10.1043/2010-0226-CR.1. PMID 20923300.
  9. Alexiev, BA.; Levea, CM. (Mar 2012). "Nephrogenic Adenoma of the Urinary Tract: A Review.". Int J Surg Pathol. doi:10.1177/1066896912439095. PMID 22415059.
  10. Tong, GX.; Melamed, J.; Mansukhani, M.; Memeo, L.; Hernandez, O.; Deng, FM.; Chiriboga, L.; Waisman, J. (Mar 2006). "PAX2: a reliable marker for nephrogenic adenoma.". Mod Pathol 19 (3): 356-63. doi:10.1038/modpathol.3800535. PMID 16400326.
  11. Fromont, G.; Barcat, L.; Gaudin, J.; Irani, J. (Nov 2009). "Revisiting the immunophenotype of nephrogenic adenoma.". Am J Surg Pathol 33 (11): 1654-8. doi:10.1097/PAS.0b013e3181b40061. PMID 19730362.
  12. 12.0 12.1 Malpica, A.; Ro, JY.; Troncoso, P.; Ordoñez, NG.; Amin, MB.; Ayala, AG. (Apr 1994). "Nephrogenic adenoma of the prostatic urethra involving the prostate gland: a clinicopathologic and immunohistochemical study of eight cases.". Hum Pathol 25 (4): 390-5. PMID 7512941.
  13. Aldenborg, F.; Peeker, R.; Fall, M.; Olofsson, A.; Enerbäck, L. (Jul 1998). "Metaplastic transformation of urinary bladder epithelium: effect on mast cell recruitment, distribution, and phenotype expression.". Am J Pathol 153 (1): 149-57. doi:10.1016/S0002-9440(10)65555-1. PMID 9665475.
  14. 14.0 14.1 14.2 Shen, Q.; Sun, LH.; Wang, JH.; Liu, LB.; He, Q.; Jin, J. (Aug 2013). "[Pathological and immunohistochemical analyses of 32 cases of nephrogenic adenoma].". Beijing Da Xue Xue Bao 45 (4): 522-6. PMID 23939154.