Renal hybrid oncocytic/chromophobe tumour

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Renal hybrid oncocytic/chromophobe tumour, also hybrid oncocytic/chromophobe tumour (abbreviated HOCT) and hybrid tumour, is a rare kidney tumour with features of chromophobe renal cell carcinoma and renal oncocytoma.[1]

Renal hybrid oncocytic/chromophobe tumour
Diagnosis in short

Hybrid oncocytic/chromophobe tumour of the kidney. H&E stain.

Synonyms hybrid tumour

LM features of renal oncocytoma and chromophobe renal cell carcinoma - varies by subtype
Subtypes as per Hes et al.: (1) collision tumour-type, (2) renal oncocytoma with scattered chromophobe cells-type, (3) large eosinophilic cells with intracytoplasmic vacuoles-type
LM DDx renal oncocytoma, chromophobe renal cell carcinoma, renal cell carcinoma, unclassified, SDH-deficient renal cell carcinoma, other renal tumours with eosinophilic cytoplasm
Stains Hale's colloidal iron +ve
IHC CD117 +ve, CK7 +ve (variable)
Molecular no features of ChRCC
Grossing notes partial nephrectomy grossing, total nephrectomy for tumour grossing
Site kidney - see kidney tumours

Syndromes Birt–Hogg–Dubé syndrome

Clinical history renal mass
Prevalence very rare
Prognosis good on very limited data
Treatment surgical excision

General

  • Rare.
  • Molecular heterogeneous group[1] - may represent several different entities.
  • Prognosis good - based on one series of 11 cases.[2]

May be seen in several contexts:[1]

Microscopic

Three morphologic patterns as per Hes et al.:[1]

  1. Renal oncocytoma and chromophobe renal cell carcinoma collision tumour.
    • Different fields viewed in isolation would be compatible with the different diagnoses. Tumour component do not intermingle.
  2. Renal oncocytoma with scattered chromophobe cells.
  3. Large eosinophilic cell with intracytoplasmic vacuoles.

DDx:

Images

Case 1

Case 2

Stains

Features:[2]

IHC

Features:

  • CD117 +ve (practically definitional[1]).
  • CK7 +ve - often variable/patchy (oncocytoma-like).[2]

Others:

  • Vimentin -ve.
  • EMA +ve.
  • CD10 +ve.
  • PAX8 +ve.

Molecular

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Left Kidney, Partial Nephrectomy:
- Renal tumour with eosinophilic cytoplasm of undetermined malignant potential 
  in keeping with the so called "hybrid oncocytic/chromophobe tumour", see comment. 
-- Resection margins clear.
-- Tumour limited to kidney.

Comment:
The tumour may be seen in the context of Birt–Hogg–Dubé syndrome.

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 Hes, O.; Petersson, F.; Kuroda, N.; Hora, M.; Michal, M. (Oct 2013). "Renal hybrid oncocytic/chromophobe tumors - a review.". Histol Histopathol 28 (10): 1257-64. PMID 23740406.
  2. 2.0 2.1 2.2 2.3 Poté, N.; Vieillefond, A.; Couturier, J.; Arrufat, S.; Metzger, I.; Delongchamps, NB.; Camparo, P.; Mège-Lechevallier, F. et al. (Jun 2013). "Hybrid oncocytic/chromophobe renal cell tumours do not display genomic features of chromophobe renal cell carcinomas.". Virchows Arch 462 (6): 633-8. doi:10.1007/s00428-013-1422-4. PMID 23708994.
  3. Trpkov, K.; Yilmaz, A.; Uzer, D.; Dishongh, KM.; Quick, CM.; Bismar, TA.; Gokden, N. (Dec 2010). "Renal oncocytoma revisited: a clinicopathological study of 109 cases with emphasis on problematic diagnostic features.". Histopathology 57 (6): 893-906. doi:10.1111/j.1365-2559.2010.03726.x. PMID 21166703.