Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA.
Departments of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya, Japan.
Histopathology. 2021 Sep;79(3):338-346. doi: 10.1111/his.14296. Epub 2021 Mar 31.
Salivary gland intraductal carcinoma (IDC) is a complex ductal neoplasm surrounded by a layer of myoepithelial cells. Recent insights have shown that there are three different types: intercalated duct-like, with frequent NCOA4-RET fusions; apocrine, with salivary duct carcinoma-like mutations; and mixed intercalated duct-like/apocrine, with RET fusions, including TRIM27-RET. In addition, an oncocytic IDC has been described, but it remains unclear whether it represents a fourth variant or simply oncocytic metaplasia of another IDC type. Our aim was to more completely characterize oncocytic IDC.
Six IDCs with oncocytic changes were retrieved from the authors' archives, from three men and three women ranging in age from 45 to 75 years (mean, 63 years). Five arose in the parotid gland, with one in an accessory parotid gland. Four patients with follow-up were free of disease after 1-23 months. Several immunostains (S100, mammaglobin, androgen receptor, and p63/p40) and molecular tools (RNA sequencing, RET fluorescence in-situ hybridisation, BRAF V600E VE1 immunohistochemistry, and Sanger sequencing) were applied. Histologically, the tumours were variably cystic with solid intracystic nodules often difficult to recognise as intraductal. In all, tumour ducts were positive for S100 and mammaglobin, negative for androgen receptor, and completely surrounded by myoepithelial cells positive for p63/p40. Molecular analysis revealed TRIM33-RET in two of six cases, NCOA4-RET in one of six cases, and BRAF V600E in two of six cases. One case had no identifiable alterations.
Oncocytic IDC shares similarities with intercalated duct-like IDC. Although additional verification is needed, the oncocytic variant appears to be sufficiently unique to be now regarded as the fourth distinct subtype of IDC. Because of its indolent nature, oncocytic IDC should be distinguished from histological mimics.
唾液腺导管内癌（IDC）是一种复杂的导管性肿瘤，周围环绕着一层肌上皮细胞。最近的研究表明，IDC 有三种不同的类型：具有高频 NCOA4-RET 融合的闰管样型；具有唾液腺癌样突变的大汗腺型；以及具有 RET 融合的混合闰管样/大汗腺型，包括 TRIM27-RET。此外，还描述了一种嗜酸细胞性 IDC，但它是否代表第四种变异型，还是另一种 IDC 类型的嗜酸细胞化生尚不清楚。我们的目的是更全面地描述嗜酸细胞性 IDC。
从作者的档案中检索到 6 例具有嗜酸细胞改变的 IDC，患者为 3 男 3 女，年龄 45 至 75 岁（平均 63 岁）。5 例发生于腮腺，1 例发生于副腮腺。4 例有随访的患者在 1-23 个月后无疾病。应用了多种免疫组化染色（S100、乳球蛋白、雄激素受体和 p63/p40）和分子工具（RNA 测序、RET 荧光原位杂交、BRAF V600E VE1 免疫组化和 Sanger 测序）。组织学上，肿瘤呈不同程度的囊性，实性腔内结节常难以识别为腔内。总之，肿瘤导管 S100 和乳球蛋白阳性，雄激素受体阴性，完全被 p63/p40 阳性的肌上皮细胞环绕。分子分析显示，6 例中有 2 例存在 TRIM33-RET，6 例中有 1 例存在 NCOA4-RET，6 例中有 2 例存在 BRAF V600E。1 例无可识别的改变。
嗜酸细胞性 IDC 与闰管样 IDC 具有相似性。尽管需要进一步验证，但该嗜酸细胞变异型似乎足够独特，现在可以被视为 IDC 的第四种独特亚型。由于其惰性性质，嗜酸细胞性 IDC 应与组织学模拟物区分开来。
