Papillary renal neoplasm with reverse polarity

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Papillary renal neoplasm with reverse polarity
Diagnosis in short

Papillary renal neoplasm with reverse polarity. H&E stain.

LM papillary structures, eosinophilic cytoplasm, reverse polarity of nuclei (nuclei at luminal aspect of cell), low nuclear grade
LM DDx eosinophilic papillary renal cell carcinoma, other renal tumours with eosinophilic cytoplasm
IHC GATA3 +ve, PAX-8 +ve, CK7 +ve, CD10 +ve, CD117 -ve
Molecular KRAS mutations
Grossing notes partial nephrectomy, radical nephrectomy
Site kidney - see kidney tumours

Prevalence rare
Prognosis indolent - based on limited data
Clin. DDx other kidney tumours

Papillary renal neoplasm with reverse polarity is a rare renal tumour and an evolving entity.[1] It has a distinctive morphology that matches the name.

General

Micro

Features:[1]

  • Branching papillae with:
    • Thin fibrovascular cores.
    • Cuboidal to columnar lining cells with granular eosinophilic cytoplasm.
      • May have occasional cytoplasmic clearing.
    • Smooth luminal borders.
    • Reverse polarized nuclei (luminal nuclei; nuclei closer to lumen than basement membrane).
    • Nucleoli absent or small.

DDx:

Images

IHC

Features:[1]

  • CK7 +ve (88% +ve, 37 of 42 cases[3]).
  • CD10 +ve/-ve (50% +ve, 21 of 42 cases[3]).
  • GATA3 +ve (43 of 43 cases[3]).
    • Negative in other papillary RCCs.[3]
  • Vimentin -ve (all cases).
  • CD117 -ve.
  • AE1/AE3 +ve.
  • EMA +ve.
  • L1CAM +ve.
  • AMACR -ve (4 of 43 cases[3]).
  • RCC -ve (1 of 43 cases[3]).

Stains that help differentiate between papillary RCC and PRNRP adapted from Kim et al.[3]

Diagnosis GATA3 AMACR RCC Vimentin
Papillary RCC 0% +ve 85-90% +ve 60-75% +ve 60-70% +ve
PRNRP 100% +ve ~10% +ve ~2% +ve ~2% +ve

Molecular

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A. Right Kidney, Tumour, Partial Nephrectomy:
	- Papillary renal neoplasm with reverse polarity, clear of margin, see comment.

Comment:
The tumour has a papillary architecture, eosinophilic cytoplasm, low nuclear grade, and reversed nuclear polarity.

It stains as follows:
POSITIVE: PAX8 (moderate, diffuse), CK7 (strong, diffuse), AE1/AE3 (strong, diffuse), GATA3 (moderate, diffuse), AMACR (moderate, diffuse).
NEGATIVE: vimentin (stroma), CD117, CD10.

The findings are in keeping with papillary renal neoplasm with reverse polarity (PRNRP). PRNRP is thought to be distinct from papillary RCC.[1][2]  Limited data suggests PRNRP has an indolent behaviour.[3] Follow-up is recommended. 

1. Pathol Int. 2024 Apr;74(4):222-226. doi: 10.1111/pin.13417. https://pubmed.ncbi.nlm.nih.gov/38456605/
2. Hum Pathol. 2023 Dec:142:1-6. doi: 10.1016/j.humpath.2023.09.011. https://pubmed.ncbi.nlm.nih.gov/37797754/
3. Am J Surg Pathol. 2019 Aug;43(8):1099-1111. doi: 10.1097/PAS.0000000000001288. https://pubmed.ncbi.nlm.nih.gov/31135486/

See also

References

  1. 1.0 1.1 1.2 1.3 Al-Obaidy KI, Eble JN, Cheng L, Williamson SR, Sakr WA, Gupta N, Idrees MT, Grignon DJ (August 2019). "Papillary Renal Neoplasm With Reverse Polarity: A Morphologic, Immunohistochemical, and Molecular Study". Am J Surg Pathol 43 (8): 1099–1111. doi:10.1097/PAS.0000000000001288. PMID 31135486.
  2. Castillo VF, Trpkov K, Van der Kwast T, Rotondo F, Hamdani M, Saleeb R (April 2024). "Papillary renal neoplasm with reverse polarity is biologically and clinically distinct from eosinophilic papillary renal cell carcinoma". Pathol Int 74 (4): 222–226. doi:10.1111/pin.13417. PMID 38456605.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Kim B, Lee S, Moon KC (December 2023). "Papillary renal neoplasm with reverse polarity: a clinicopathologic study of 43 cases with a focus on the expression of KRAS signaling pathway downstream effectors". Hum Pathol 142: 1–6. doi:10.1016/j.humpath.2023.09.011. PMID 37797754.