Pathology Section, Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, Italy.
Section of Anatomic Pathology, Department G.F. Ingrassia, University of Catania, Catania, Italy.
Head Neck Pathol. 2021 Dec;15(4):1359-1371. doi: 10.1007/s12105-021-01290-z. Epub 2021 Jan 27.
Low-grade intraductal carcinoma is a rare neoplasia with an excellent prognosis, previously classified as low-grade cribriform cystadenocarcinoma and low-grade salivary duct carcinoma. The tumor mainly occurs in the parotid gland and presents a ductal phenotype and an intraductal/intracystic growth pattern. It resembles intraductal breast lesions such as atypical ductal hyperplasia, papillary and cribriform ductal carcinoma in situ. Despite its infrequency, discriminating low-grade intraductal carcinoma from other salivary gland tumors is crucial, especially because of its favorable prognosis. A 74-year-old woman with a history of neurofibromatosis underwent a superficial parotidectomy to remove a sharply demarcated multi-cystic mass, diagnosed as category 4 at FNAC. The histological examination revealed a demarcated but unencapsulated lesion composed of a bigger cyst surrounded by several smaller cysts, lined by a monolayer or bilayer epithelium alternated with a cribriform proliferation, characterized by "Roman-bridges", with occasional micro-papillae. A myoepithelial component, with a basal disposition, was present, confirmed by intense staining for protein p63 and SMA. Immunohistochemical stains showed intense, strong uniform positivity for pan-cytokeratin, protein S100, and SOX10. The Ki67 proliferation index was low (< 10%). A diagnosis of Low-grade Intraductal Carcinoma (LGIC) of the parotid was made. We performed a literature search in PUBMED for "Intraductal carcinoma", "Low-grade Intraductal Carcinoma", "Cribriform Cystadenocarcinoma", "Salivary Duct Carcinoma", and "Low-Grade Salivary Duct Carcinoma". We selected 17 papers published between 1983 and 2020; the most affected anatomical site was the parotid gland (77/90), followed by minor salivary glands (6/90), the intraparotid lymph nodes (3/90) and the submandibular gland (4/90). Their main histopathological features are reported in the paper. Here we present a case report and a review of scientific literature on this topic to provide some essential diagnostic tools to discriminate this rare entity.
低级别管内癌是一种罕见的肿瘤，具有极好的预后，以前被归类为低级别筛状囊腺癌和低级别唾液腺癌。该肿瘤主要发生在腮腺，表现为导管表型和导管内/囊内生长模式。它类似于导管内乳腺病变，如非典型导管增生、乳头状和筛状原位导管癌。尽管其罕见，但区分低级别管内癌与其他唾液腺肿瘤至关重要，尤其是因为其预后良好。一位 74 岁的女性，患有神经纤维瘤病，曾行腮腺浅叶切除术切除界限清楚的多房囊性肿块，FNAC 诊断为 4 类。组织学检查显示界限清楚但无包膜的病变，由一个较大的囊肿周围有几个较小的囊肿组成，由单层或双层上皮细胞交替排列的筛状增生所衬里，具有“罗马桥”特征，偶尔有微乳头。存在基底排列的肌上皮成分，通过强烈的蛋白 p63 和 SMA 染色得到证实。免疫组织化学染色显示全细胞角蛋白、S100 蛋白和 SOX10 强阳性、均匀阳性。Ki67 增殖指数低（<10%）。诊断为腮腺低级别管内癌（LGIC）。我们在 PUBMED 中以“管内癌”、“低级别管内癌”、“筛状囊腺癌”、“唾液腺癌”和“低级别唾液腺癌”为关键词进行了文献检索。我们选择了 1983 年至 2020 年期间发表的 17 篇论文；受影响最严重的解剖部位是腮腺（77/90），其次是小唾液腺（6/90）、腮腺内淋巴结（3/90）和颌下腺（4/90）。本文报告了一个病例报告，并对该主题的科学文献进行了综述，以提供一些必要的诊断工具来区分这种罕见实体。
