Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
Graduate Institute of Pathology, National Taiwan University College of Medicine, Taipei, Taiwan.
Virchows Arch. 2020 Oct;477(4):581-592. doi: 10.1007/s00428-020-02823-7. Epub 2020 May 7.
Intraductal carcinoma (IC) is a rare salivary gland tumor with low- to intermediate-grade cytological features. It is further classified into intercalated duct type and apocrine type based on its distinct histologic and immunohistochemical expression. Conventional salivary duct carcinoma (SDC) is an aggressive carcinoma with high-grade features and is usually associated with poor prognosis. In this study, immunohistochemistry and mutation analyses (including HRAS/PIK3CA mutations, RET rearrangement, and human epidermal growth factor receptor 2 [HER2] amplification) of 9 ICs (including 3 pure ICs, 6 ICs with invasive carcinoma) and 24 conventional SDCs were performed and the results were compared. Four intercalated duct-type cases were positive for SOX10 and S100 and negative for AR; five apocrine-type cases showed opposite results. All five apocrine-type cases had cysts with relatively circumscribed tumor borders and morphologically mimicking breast low-grade ductal carcinoma in situ or papillary carcinoma. RET fusion is detected in half of the 4 intercalated duct-type IC but not in the apocrine-type or conventional SDC. HER2 amplification was only observed in conventional SDC. The monoclonal antibody (clone RBT-NRAS) against NRAS Q61R is a sensitive and specific marker used for detecting HRAS Q61R mutation in the salivary gland tumors. The apocrine-type IC had different cytological grades, distinct tumor growth patterns, and no evidence of low- to high-grade transition, suggesting that apocrine-type IC should be distinguished from apocrine SDC with an in situ component.
导管内癌（IC）是一种罕见的低至中度细胞特征的唾液腺肿瘤。根据其独特的组织学和免疫组织化学表现，进一步分为间插导管型和大汗腺型。传统的涎腺导管癌（SDC）是一种侵袭性的高级别肿瘤，通常与预后不良相关。在这项研究中，对 9 例 IC（包括 3 例纯 IC 和 6 例伴浸润性癌的 IC）和 24 例常规 SDC 进行了免疫组织化学和突变分析（包括 HRAS/PIK3CA 突变、RET 重排和人表皮生长因子受体 2 [HER2]扩增），并比较了结果。4 例间插导管型病例 SOX10 和 S100 阳性，AR 阴性；5 例大汗腺型病例结果相反。所有 5 例大汗腺型病例均有囊腔，肿瘤边界相对界限清楚，形态上类似于乳腺低级别导管原位癌或乳头状癌。4 例间插导管型 IC 中有一半检测到 RET 融合，但在大汗腺型或常规 SDC 中未检测到。HER2 扩增仅见于常规 SDC。针对 NRAS Q61R 的单克隆抗体（克隆 RBT-NRAS）是一种敏感且特异的标志物，用于检测唾液腺肿瘤中的 HRAS Q61R 突变。大汗腺型 IC 具有不同的细胞学分级、明显的肿瘤生长模式，且无低级别至高级别转化的证据，提示大汗腺型 IC 应与具有原位成分的大汗腺型 SDC 相区别。
