Recognition of nonkeratinizing morphology in oropharyngeal squamous cell carcinoma - a prospective cohort and interobserver variability study.
OBJECTIVE
Nonkeratinizing morphology in oropharyngeal squamous cell carcinoma (NKSCC) strongly correlates with human papillomavirus and p16 status, but as a unique diagnostic entity is not widely recognized by pathologists. We sought to prospectively examine the performance of a new histological typing system during 1 year of routine clinical practice (Aim 1) and also its reproducibility amongst six head and neck pathologists using a 40 case test set (Aim 2).


RESULTS
The three histological types were: Type 1 (keratinizing), Type 2 (nonkeratinizing with maturation) and Type 3 (nonkeratinizing). For Aim 1, there were 85 cases. p16 immunohistochemistry was positive in five of the 18 (27.8%) cases classified as Type 1, 18 of the 19 (94.7%) as Type 2, and 47 of the 48 (97.9%) as Type 3. For Aim 2, agreement among pathologists on the test cases was best for types 1 and 3 (kappa values 0.62 and 0.56; P < 0.0001) and lowest for type 2 (kappa 0.35; P < 0.0001). All 21 cases classified as NK SCC (type 3) by any of the reviewers was p16 positive.


CONCLUSIONS
Pathologists can recognize NK SCC with good agreement, and when a pathologist classifies a tumour as NK SCC, this reliably predicts p16 positivity.
Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA. jlewis@path.wustl.edu
James S
JS
Lewis
Raja A
RA
Khan
Ramya P
RP
Masand
Rebecca D
RD
Chernock
Qin
Q
Zhang
Nasser Said
NS
Al-Naief
Susan
S
Muller
Jonathan B
JB
McHugh
Manju L
ML
Prasad
Margaret
M
Brandwein-Gensler
Bayardo
B
Perez-Ordonez
Samir K
SK
El-Mofty
D014408:Biomarkers, Tumor / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007633:Keratins / Q000378:metabolism*; D015588:Observer Variation; D009959:Oropharyngeal Neoplasms / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D025803:Tumor Suppressor Protein p14ARF / Q000378:metabolism*
D014408:Biomarkers, Tumor; D025803:Tumor Suppressor Protein p14ARF; D007633:Keratins