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)
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

TCEB1-mutated renal cell carcinoma, also renal cell carcinoma with TCEB1 mutation, is an evolving entity that is morphologically similar to clear cell renal cell carcinoma and clear cell tubulopapillary renal cell carcinoma.[1]

It should not be confused with TFEB renal cell carcinoma, also known as renal tumour with t(6;11) translocation.

This entity is not recognized by the WHO classification of renal neoplasia. It probably represents 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]

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Molecular lacking

Left Kidney, Partial Nephrectomy:
- Renal cell carcinoma (RCC) with clear cells and leiomyomatous stroma, 
  favour clear cell RCC, see comment.
- ISUP nucleolar grade 2/4.
- TMN stage: pT1a pNx
- Please see synoptic report.

Comment:
The tumour stains as follows:
POSITIVE: CK7, CD10.
NEGATIVE: CK34betaE12, CD34, CK20.

The staining and morphology raises the possibility of a TCEB-1 mutation, described 
in a subset of clear cell RCC. 

The differential diagnosis includes clear cell renal cell carcinoma and clear cell 
papillary RCC.  Clear cell RCC is favoured.

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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