Dababneh Melad N, Azzato Elizabeth M, Nakitandwe Joy, Cracolici Vincent, Shah Akeesha A
Department of Pathology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA.
Robert J. Tomsich Department of Pathology and Laboratory Medicine, Cleveland Clinic, Cleveland, OH, USA.
Histopathology. 2025 Feb;86(3):385-396. doi: 10.1111/his.15334. Epub 2024 Oct 3.
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.
具有显著小梁状/小管状形态的多形性腺瘤（PA）具有一致的HMGA2蛋白表达，并与HMGA2融合相关。我们报告了我们对该亚型的经验，重点关注在此背景下可能发生的癌。
对具有显著小梁状/小管状形态的大唾液腺肿瘤进行回顾性和前瞻性研究（2013 - 2024年）。21例腮腺肿瘤符合标准：14例为良性（66.7%），6例为癌（28.6%），1例行为不确定（4.7%）。对所有病例进行了HMGA2免疫组织化学（IHC）检测。18例成功进行了二代测序。7例良性病例有传统PA成分。在所有病例中，这些小梁状/小管状区域的肿瘤细胞表现出可变的甲状腺乳头状癌样核变化，包括染色质清除、核拥挤、膜不规则和核内假包涵体。良性肿瘤界限清楚，而癌表现为多结节浸润模式或微小浸润。2例癌显示细胞学异型性增加和结构复杂性增加，1例有神经周浸润。通过IHC，所有病例HMGA2均为阳性。在小梁状/小管状区域，CAM5.2、S - 100和SOX - 10均呈一致强表达，p63表达可变但p40阴性。18例中有16例（89%）检测到HMGA2改变。2例癌有随访资料，1例局部复发。
虽然大多数具有显著小梁状/小管状生长模式的HMGA2阳性唾液腺肿瘤是良性的，但与传统PA一样，它们可能会发生局部复发的癌。这些癌可能看似平淡、微小浸润或具有多结节浸润模式。
