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Case Reports
. 2025 Aug 11:15:1605192.
doi: 10.3389/fonc.2025.1605192. eCollection 2025.

Synchronous papillary renal neoplasm with reverse polarity and multilocular cystic renal neoplasm of low malignant potential in unilateral kidney: case report with molecular analysis and literature review

Pichayut Nithagon  1 , Joeffrey Chahine  1 , Lambros Stamatakis  2 , Rashmi Samdani  1
Affiliations
Case Reports

Synchronous papillary renal neoplasm with reverse polarity and multilocular cystic renal neoplasm of low malignant potential in unilateral kidney: case report with molecular analysis and literature review

Pichayut Nithagon et al. Front Oncol. .

Abstract

Papillary Renal Neoplasm with Reverse Polarity (PRNRP) is a rare renal tumor, recently described in 2019 by Al-Obaidy et al. defined by characteristic histology of papillary neoplasm with apically located WHO/ISUP grade 1nuclei and frequent KRAS mutations. Multilocular cystic renal neoplasm of low malignant potential (MC-LMP) is an indolent tumor with a characteristic multicystic appearance with cysts lined by WHO/ISUP nuclear grade1 clear cells and presence of VHL alterations similar to that of clear cell renal cell carcinoma (ccRCC); therefore, considered its variant. Simultaneous occurrence of both these tumor types that are immunophenotypically and genetically distinct within same kidney is extremely rare and this is the first case report to date. Herein, we report a case of a 70-year-old male who was incidentally found to have bilateral renal cysts on imaging follow up for cardiovascular problems. The diagnosis of PRNRP and MC-LMP within the same kidney was made on histology in conjunction with ancillary tests. Awareness of PRNRP and MC-LMP is crucial for accurate diagnosis, as these tumors often resemble some of the aggressive variants of Renal cell carcinoma (RCC), such as Papillary RCC (pRCC) and ccRCC respectively on histology. Ability to correctly identify these indolent tumors is essential for optimal treatment options as they are often amenable to partial nephrectomy. This case underscores the need for further research into the pathogenesis and clinical implications of synchronous renal tumors with distinct immunophenotypes, and genomic profiles within the same kidney.

Keywords: KRAS mutation; multiloculate cystic renal neoplasm of low malignancy potential; papillary renal neoplasm with reverse polarity; renal neoplasm pathogenesis; synchronous renal tumors.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Abdominal MRI images showing (A, B) mass within anterior upper pole of left kidney with thick irregular internal septation (arrow). Image (C) demonstrates additional cysts in both kidneys.
Figure 2
Figure 2
(A) PRNRP showing oncocytic cells with low-grade reversed nuclei polarity and papillary architecture and (B) higher power image. Immunohistochemistry for (C) CK7 is positive, (D) CD117 is negative, (E) GATA3 shows positive nuclear staining, (F) CAIX is negative, and (G) AMCAR is negative.
Figure 3
Figure 3
(A, B) MC-LMP with higher power. Immunohistochemistry for (C) CK7 is positive, and (D) CAIX is positive.
See this image and copyright information in PMC

References

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