WHO soft tissue and bone tumour classification reaches a sixth edition, a three-marker panel tests lung carcinoid biopsies, and tumour content decides genomic profiling success

The edition in brief

The sixth edition of the WHO Classification of Soft Tissue and Bone Tumours was drafted by 203 editors and authors from 27 countries. It adds 19 new entities, refines essential and desirable diagnostic criteria for different resource settings, and replaces the term variant with morphological pattern for features that do not change behaviour; it lists 116 soft tissue tumours, 46 bone tumours and 62 sarcomas in all. In a Dutch registry cohort of 98 resected lung neuroendocrine tumours with 19 relapses, a panel of OTP, CD44 and Ki-67 immunohistochemistry on preoperative biopsies flagged 89% of relapses as high risk against 11% for the WHO atypical carcinoid label, with higher interobserver agreement (kappa 0.673 against 0.276), though the cohort is small and retrospective. A nine-feature H&E image score (TIGERS) in resected pancreatic cancer improved the C-index in all six retrospective cohorts and gave a hazard ratio of 4.45 (95% CI 2.28-8.70) in a prospective cohort of 155, but its fixed cutoff failed to transfer to one external cohort, where 96.2% were called high risk. A single-centre audit of 371 FoundationOne CDx requests found 14.0% were cancelled before submission and 13.8% of returned results were only Qualified; low tumour content was the only independent predictor of failure.