Papillary thyroid carcinoma tall cell subtype (PTC‐TC) and high‐grade differentiated thyroid carcinoma tall cell phenotype (HGDTC‐TC) have different clinical behaviour: a retrospective study of 1456 patients

Papillary thyroid carcinoma, tall cell subtype (PTC-TC) is a potentially aggressive histotype. The latest World Health Organisation (WHO) classification introduced a novel class of tumours; namely, high-grade differentiated thyroid carcinoma (HGDTC), characterised by elevated mitotic count and/or necrosis, which can exhibit a tall cell phenotype (HGDTC-TC).