Reliability of the histopathologic diagnosis of keratinocyte carcinomas.
OBJECTIVE
We sought to determine the interobserver reliability of the histopathologic diagnosis of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) (keratinocyte carcinomas) in the setting of a Department of Veteran Affairs multicenter chemoprevention study.


METHODS
Interobserver concordance was assessed by blinded review of histopathologic slides by study dermatopathologists.


RESULTS
Overall interobserver agreement between the two dermatopathogists was kappa = 0.69 (95% confidence interval [CI] 0.67-0.69). The dermatopathologists' interobserver agreement was highest for basal cell carcinoma at kappa = 0.88 (95% CI 0.84-0.91) and for a diagnostic category in the SCC-actinic keratosis spectrum at kappa = 0.80 (95% CI 0.73-0.86). The largest disagreements between the two reference dermatopathologists were regarding the categories of invasive SCC at kappa = 0.62 (95% CI 0.52-0.72), SCC in situ at kappa = 0.42 (95% CI 0.29-0.56), and actinic keratosis at kappa = 0.51 (95% CI 0.40-0.62). Agreement between the local pathologists and central reference dermatopathologists were similar to the agreement between the central dermatopathologists. The morphea subtype of basal cell carcinoma was the only reliably diagnosed subtype (kappa = 0.79, 95% CI 0.51-1.00), and tumor depth was reliably measured.


CONCLUSIONS
A limitation of this study was the use of only two reference dermatopathologists.


CONCLUSIONS
Because of the impact on physician decision making and patient care, researchers and clinicians need to be aware of reliability of histopathology results, particularly pertaining to the SCC and actinic keratosis spectrum.
Jagdeo
Jared
J
Dermatoepidemiology Unit, Providence Veterans Affairs Medical Center, Providence, RI 02908, USA.
Weinstock
Martin A
MA
Piepkorn
Michael
M
Bingham
Stephen F
SF
D001706:Biopsy / Q000592:standards; D002280:Basal Cell Carcinoma / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D004428:Ear Neoplasms / Q000473:pathology*; D005153:Facial Neoplasms / Q000473:pathology*; D006801:Humans; D015603:Keratinocytes / Q000473:pathology; D007641:Keratolytic Agents / Q000627:therapeutic use; D007642:Keratosis / Q000473:pathology / Q000517:prevention & control; D009361:Neoplasm Invasiveness / Q000473:pathology; D015588:Observer Variation; D010787:Photosensitivity Disorders / Q000473:pathology / Q000517:prevention & control; D015203:Reproducibility of Results; D014212:Tretinoin / Q000627:therapeutic use
D007641:Keratolytic Agents; D014212:Tretinoin