具有突出小梁/小管形态的多形性腺瘤 (PA) 具有一致的 HMGA2 蛋白表达，并与 HMGA2 融合相关。我们报告我们在这种亚型方面的经验，重点是在这种情况下可能出现的癌症。对具有突出小梁/小管形态的主要唾液腺肿瘤进行了回顾性和前瞻性回顾（2013-2024）。 21 例腮腺肿瘤符合标准：14 例良性（66.7%）、6 例癌（28.6%）和 1 例行为不确定（4.7%）。对所有病例进行 HMGA2 免疫组织化学 (IHC)。 18日成功进行二代测序。7例良性病例具有常规PA成分。在所有病例中，这些小梁/小管区域的肿瘤细胞表现出可变的乳头状甲状腺癌样核变化，包括染色质清除、过度拥挤、膜不规则和核内假包涵体。良性肿瘤界限清楚，而癌则表现出多结节性浸润或微妙浸润。两种癌表现出细胞学异型性和结构复杂性增加，一种具有神经周围浸润。通过 IHC，所有 HMGA2 均呈阳性。在小梁/小管区域，CAM5.2、S-100 和 SOX-10 一致强表达，p63 表达可变，但 p40 阴性。 18 例中有 16 例 (89%) 检测到 HMGA2 改变。对两种癌症进行了随访，其中一种是局部复发的。虽然大多数具有显着小梁/小管生长模式的 HMGA2 阳性唾液腺肿瘤是良性的，但它们与传统 PA 一样，可能会导致局部复发的癌症。这些癌可能是看似平淡的、微妙的浸润性或具有多结节性浸润模式。© 2024 John Wiley

Pleomorphic adenoma (PA) with a prominent trabecular/canalicular morphology has consistent HMGA2 protein expression, and association with HMGA2 fusions. We report our experience with this subtype, with emphasis on the carcinomas that can arise in this context.A retro- and prospective review (2013-2024) of major salivary gland tumours with prominent trabecular/canalicular morphology was performed. Twenty-one parotid tumours met the criteria: 14 benign (66.7%), six carcinomas (28.6%), and one of uncertain behaviour (4.7%). HMGA2 immunohistochemistry (IHC) was performed on all cases. Next-generation sequencing was successfully performed on 18. Seven benign cases had a conventional PA component. In all cases, the tumour cells in these trabecular/canalicular areas demonstrated variable papillary thyroid carcinoma-like nuclear changes, including chromatin clearing, overcrowding, membrane irregularities, and intranuclear pseudoinclusions. Benign tumours were well-demarcated, whereas carcinomas demonstrated either a multinodular pattern of invasion or subtle infiltration. Two carcinomas showed increased cytologic atypia and architectural complexity and one had perineural invasion. By IHC, all were positive for HMGA2. In the trabecular/canalicular areas, there was consistent strong expression of CAM5.2, S-100, and SOX-10 and variable expression of p63 but negative p40. HMGA2 alterations were detected in 16 of 18 cases (89%). Follow-up was available on two carcinomas, with one being locally recurrent.While most HMGA2-positive salivary gland neoplasms with a prominent trabecular/canalicular growth pattern are benign, they, like traditional PAs, may give rise to carcinomas that can locally recur. These carcinomas can be deceptively bland, subtly infiltrative, or have a multinodular pattern of invasion.© 2024 John Wiley & Sons Ltd.