Consistency of histopathological reporting of laryngeal dysplasia. The Scottish Pathology Consistency Group

Clinical management of premalignant and malignant lesions of the larynx is dependent on histopathological evaluation. The Scottish Pathology Consistency Group assessed interobserver variation in the evaluation of laryngeal dysplasia.

One hundred laryngeal biopsies ranging from normal to invasive carcinoma were assessed. The overall Kappa result of 0.32 was disappointing. However, agreement on those categories which dictate significantly different management was more favourable. The Kappa figure for mild dysplasia versus severe dysplasia/CIS was 0.7, the Kappa figure for mild dysplasia versus severe dysplasia/CIS and invasive carcinoma was 0.77. The Kappa figure for mild and moderate dysplasia versus severe dysplasia/ CIS and invasive carcinoma was 0.57. An attempt to use a two grade system gave a Kappa figure of 0.52.

Our group had a satisfactory agreement on the distinction of mild from severe dysplasia and on microinvasive carcinoma without any discussion as to histopathological criteria to be used. Clinical management--review endoscopy, repeat cord stripping, radiotherapy and laryngectomy--is in general dependent on histological assessment. Thus the agreement on categories which underpin clinical management is reassuring. However, assessment of moderate dysplasia remains problematic. An attempt to utilize a two grade system--low grade from high grade dysplasia/CIS--may have merit. The implications of the terminology used must be agreed among pathologists and clinicians working closely within clinicopathological cancer groups.