Kusafuka Kimihide, Kawasaki Takuya, Nakajima Takashi, Sugino Takashi
Pathology Division, Shizuoka Cancer Center, Shizuoka 411-8777, Japan.
Pathol Int. 2017 Jul;67(7):355-360. doi: 10.1111/pin.12538. Epub 2017 May 19.
Malignant non-basaloid tumors that arise from basal cell adenoma (BCA) are extremely rare. The patient was a 72-year-old Japanese male, who had noticed swelling of the left parotid region 21 years ago. A superficial lobectomy was performed. About 60% of the tumor was made up of cribriform and trabecular tissue composed of basaloid cells, which exhibited mild atypia and nuclear expression of β-catenin. This portion of the tumor was considered to be a BCA. In the other part of the tumor, the proliferation of large eosinophilic atypical cells, most of which formed intraductal structures, was observed. These tumor cells displayed cellular atypia, and some of them formed Roman bridge structures or contributed to intracapsular invasion. Immunohistochemically, these cells were positive for cytokeratin 7, gross cystic disease fluid proten-15 (GCDFP-15), androgen receptor (AR), and mammaglobin (MMG) and exhibited a high Ki-67 labeling index. So, this portion of the tumor was considered to be a salivary duct carcinoma (SDC). The tumor's final diagnosis was SDC ex BCA (intracapsular type), which is extremely rare. GCDFP-15, AR, MMG, and Ki-67 are useful immunohistochemical markers for diagnosing SDC ex BCA.
源自基底细胞腺瘤（BCA）的恶性非基底样肿瘤极为罕见。该患者为一名72岁的日本男性，21年前发现左腮腺区肿胀。行浅叶切除术。肿瘤约60%由基底样细胞组成的筛状和小梁状组织构成，这些细胞表现出轻度异型性及β-连环蛋白核表达。肿瘤的这一部分被认为是BCA。在肿瘤的另一部分，观察到大量嗜酸性非典型细胞增殖，其中大部分形成导管内结构。这些肿瘤细胞表现出细胞异型性，部分形成罗马桥结构或导致包膜内侵犯。免疫组化显示，这些细胞细胞角蛋白7、巨大囊肿病液体蛋白-15（GCDFP-15）、雄激素受体（AR）和乳腺珠蛋白（MMG）呈阳性，且Ki-67标记指数较高。因此，肿瘤的这一部分被认为是涎腺导管癌（SDC）。该肿瘤的最终诊断为BCA来源的SDC（包膜内型），极为罕见。GCDFP-15、AR、MMG和Ki-67是诊断BCA来源的SDC有用的免疫组化标志物。
