Interobserver reproducibility of a grading system for chromophobe renal cell carcinoma.
OBJECTIVE
To evaluate interobserver reproducibility of a grading system proposed by Paner et al. for chromophobe renal cell carcinoma.


METHODS
After selecting 23 cases of chromophobe renal cell carcinoma from the Xeral-Cíes Hospital, Meixoeiro Hospital and POVISA Hospital from the last 15 years, an informative meeting on the Paner et al. grading system criteria was held. After, the participating pathologists applied the system to each case, evaluating one slide selected. Kappa index for interobserver reproducibility was calculated, and it was classified according to the Landis and Koch scale.


RESULTS
The grading distribution was similar for most of the 6 participating observers, with grade 1 predominance. The remaining 2 observers considered a relatively higher proportion of grade 2. Kappa index values ranged from 0.136 to 0.674, with a discrete-moderate reproducibility index predominance (0.21-0.60). Highest Kappa value (0.674) was obtained between the most novel and the most expert interobservers. The lowest Kappa value was obtained among the most veteran pathologists (0.136).


CONCLUSIONS
Interobserver reproducibility for chromophobe renal cell carcinoma is discrete-moderate in our institutions when the novel grade proposed by Paner et al. is used. Labeling of grades 1 and 2 is not homogeneous among 6 participating observers. While awaiting a grading consensus on a new classification by the scientific societies, we consider that the routine use of a grading system for chromophobe renal cell carcinoma should not be used.
Servicio de Anatomía Patológica, Hospital Xeral-Cíes, Complejo Hospitalario Universitario de Vigo, Vigo, Pontevedra, España. Electronic address: appedrosa77@gmail.com.
A
A
Pérez-Pedrosa
J A
JA
Ortiz-Rey
Y
Y
Lorenzo-Mahía
B
B
Iglesias-Rodríguez
A
A
Peteiro-Cancelo
J
J
González-Carreró
D002292:Carcinoma, Renal Cell / Q000145:classification / Q000473:pathology* / Q000648:ultrastructure; D002466:Cell Nucleolus / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D002843:Chromatin / Q000648:ultrastructure; D006801:Humans; D007680:Kidney Neoplasms / Q000145:classification / Q000473:pathology* / Q000648:ultrastructure; D060787:Neoplasm Grading / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013194:Staining and Labeling
D002843:Chromatin