In phyllodes tumours, mitoses and heterologous elements predicted metastasis better than reclassification

The edition in brief

A single-centre review of 58 borderline and malignant phyllodes tumours found that stromal mitoses of 30 or more per 10 high-power fields and malignant heterologous elements were independently associated with metastasis. The Tan classification agreed with WHO 2019 in 97% of cases, while the Refined Criteria reclassified 52% of borderline tumours as malignant and none of those metastasised during follow-up. A meta-analysis of 35 studies listed salivary gland tumours by SOX10 positivity: pleomorphic adenoma, adenoid cystic, acinic cell and polymorphous carcinoma are almost always positive; Warthin tumour, oncocytoma and salivary duct carcinoma are almost always negative; clone BC34 stained fewer tumours. In 666 resected gastric cancers, the 27 with a neuroendocrine carcinoma component had worse survival, and nodal metastases were mostly neuroendocrine. Cytology cell blocks matched FFPE tissue for hybrid-capture NGS coverage, while stained smears gave less uniform coverage. The pearl covers how to report a mixed neuroendocrine component.