ELOC-mutated renal cell carcinoma

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ELOC-mutated renal cell carcinoma
Diagnosis in short

RCC with clear cells and fibromuscular band - morphology compatible with TCEB1 mutation. H&E stain. (WC)
Synonyms TCEB1-mutated renal cell carcinoma (old name)
LM clear cells with abundant cytoplasm and basal nuclei (may have luminal nuclei), usually ISUP nucleolar grade 2, fibromuscular bands
LM DDx clear cell renal cell carcinoma, clear cell tubulopapillary renal cell carcinoma
IHC CK7 +ve, CD10 +ve, CK34betaE12 -ve
Molecular TCEB1 mutation
Site kidney - see kidney tumours
Syndromes possibly tuberous sclerosis - see tuberous sclerosis-associated renal cell carcinoma
Prevalence very rare - evolving entity
Prognosis good - based on limited data

ELOC-mutated renal cell carcinoma is a type of renal cell carcinoma that is morphologically similar to clear cell renal cell carcinoma and clear cell papillary renal cell tumour (previously clear cell papillary renal cell carcinoma).[1] It was formally recognized in the WHO 2022 classification of renal neoplasia.[citation needed]

It was previously known as TCEB1-mutated renal cell carcinoma and renal cell carcinoma with TCEB1 mutation. It should not be confused with TFEB renal cell carcinoma, also known as renal tumour with t(6;11) translocation.

It is unrelated to the previously described renal angiomyoadenomatous tumour[1][2] that was lumped with clear cell papillary renal cell carcinoma in the Vancouver modification of the WHO classification.

General

  • Evolving entity.
  • TCEB1 (transcription elongation factor B, polypeptide 1) is part of a complex that binds with the product of the VHL gene;[3] thus, it acts as a tumour suppressor.
  • Good prognosis - based on limited data.[1]

Gross

  • Cystic changes.

Microscopic

Features:

  • Clear cells with abundant cytoplasm and basal nuclei.
    • Luminal nuclei (like in clear cell tubulopapillary RCC) may be seen.
  • Usually ISUP nucleolar grade 2.
  • Fibromuscular bands - key feature.

DDx:

Images

Morphology compatible

  • RCC CCFB - very low mag.

  • RCC CCFB - low mag.

  • RCC CCFB - intermed. mag.

  • RCC CCFB - high mag.

  • RCC CCFB - high mag.

  • RCC CCFB - very high mag.

IHC

Features:[1]

Comparison between some renal tumours with clear cells

Tumour CK7 CD10 CK34betaE12 (K903)
Clear cell renal cell carcinoma -ve (may be focal) +ve -ve
Clear cell papillary renal cell tumour +ve (diffuse) -ve +ve
ELOC-mutated renal cell carcinoma +ve +ve -ve

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Molecular lacking

Right Kidney, Radical Nephrectomy: 
     - RENAL CELL CARCINOMA with clear cells, cysts and leiomyomatous stroma, see comment.
     -- Margin clear.
     -- Please see synoptic report for details.

Comment:
The tumour stains as follows:
POSITIVE: CD10 (moderate), EMA (patchy), CAM5.2, CK7 (focal), PAX8 (diffuse).
NEGATIVE: CK34betaE12, CK20.

The staining and morphology raises the possibility of a ELOC-mutated renal cell carcinoma (RCC).

The differential diagnosis includes: (1) RCC with a mTOR pathway mutation, and (2) ELOC-mutated RCC.

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 Hakimi, AA.; Tickoo, SK.; Jacobsen, A.; Sarungbam, J.; Sfakianos, JP.; Sato, Y.; Morikawa, T.; Kume, H. et al. (Jun 2015). "TCEB1-mutated renal cell carcinoma: a distinct genomic and morphological subtype.". Mod Pathol 28 (6): 845-53. doi:10.1038/modpathol.2015.6. PMID 25676555.
  2. ↑ Michal, M.; Hes, O.; Kuroda, N.; Kazakov, DV.; Hora, M. (Jun 2009). "Difference between RAT and clear cell papillary renal cell carcinoma/clear renal cell carcinoma.". Virchows Arch 454 (6): 719. doi:10.1007/s00428-009-0788-9. PMID 19471960.
  3. ↑ URL: http://www.omim.org/entry/600788. Accessed on: 12 June 2015.
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