University of South Dakota Sanford School of Medicine, Sioux Falls, South Dakota.
S D Med. 2022 Apr;75(4):158-160.
Sebaceous adenocarcinoma of the parotid gland is a rare, malignant epithelial neoplasm with focal areas of sebaceous differentiation. A literature search revealed only 34 cases as of December 2020. Our case brings this total to 35. It is characterized as a partially encapsulated neoplasm with predominant areas of basaloid or squamous cells, and variable degrees of sebaceous differentiation. The sebocytes display an immunohistochemical staining pattern of EMA (cytoplasmic vesicles), CD15, lactoferrin, GCDFP-2, and androgen receptor positivity in the sebocytes. Bimodal peaks occur in the third and seventh decades of life. We present a case of sebaceous adenocarcinoma in a 65-year-old male who initially presented in the emergency department with hypertensive urgency and vertigo. MRI and CT scans showed a heterogeneous mass with a solid component and cystic areas, including calcifications that measured approximately 2.7 x 2.1 x 4.1 cm, predominantly in the deep part of the left parotid gland and extending upward to the adjacent sternocleidomastoid muscle and possibly infiltrating or abutting the muscle. Further questioning of the patient revealed a seven month history of a painless, slow-growing mass and increased sensation of fullness on the left side of his neck. Patient underwent a left total parotidectomy with flap reconstruction and left neck dissection, revealing a 6.0 x 4.4 x 2.2 cm left parotid gland with a 2.4 x 2.2 x 1.6 cm, well-circumscribed, multiloculated cystic mass that released red-brown serous fluid and thick yellow material and appeared to abut multiple resection margins. Microscopic examination showed nests of basaloid cells at the periphery and areas of distinct sebaceous differentiation, separated by bands of extensive hyalinization. The tumor also displayed an average of 2 mitotic figures per 10 high power fields, and less nuclear atypia and less invasiveness into the surrounding glandular tissue than what has been described in sebaceous adenocarcinomas. This is an unusual case because of the rarity of the tumor as well as the lack of nuclear atypia and invasiveness compared to what is described of sebaceous adenocarcinoma in the literature.
腮腺的皮脂腺腺癌是一种罕见的、恶性的上皮性肿瘤，具有局灶性的皮脂腺分化。截至 2020 年 12 月的文献检索显示，仅有 34 例。我们的病例使总数达到 35 例。它的特点是部分被膜的肿瘤，主要区域为基底样或鳞状细胞，并有不同程度的皮脂腺分化。皮脂腺表现为 EMA（细胞质小泡）、CD15、乳铁蛋白、GCDFP-2 和雄激素受体阳性的免疫组织化学染色模式。双峰发生在第三和第七个十年。我们报告了一例 65 岁男性的皮脂腺腺癌病例，他最初因高血压急症和眩晕到急诊科就诊。MRI 和 CT 扫描显示混杂密度肿块，实性成分和囊性区域，包括钙化，大小约为 2.7 x 2.1 x 4.1 cm，主要位于左腮腺深部，向上延伸至相邻胸锁乳突肌，可能浸润或紧贴肌肉。进一步询问患者发现，他有七个月的无痛、缓慢生长的肿块，左侧颈部有饱胀感增加的病史。患者接受了左侧腮腺全切除术和皮瓣重建术以及左侧颈部淋巴结清扫术，发现左腮腺有一个 6.0 x 4.4 x 2.2 cm 的肿块，有一个 2.4 x 2.2 x 1.6 cm 的边界清楚的多房囊性肿块，释放出红棕色浆液性液体和厚黄色物质，似乎紧贴多个切除边缘。显微镜检查显示，周边有巢状的基底样细胞和明显的皮脂腺分化区域，由广泛的玻璃样变性带分隔。肿瘤还显示平均每 10 个高倍视野有 2 个有丝分裂象，核异型性和对周围腺组织的侵袭性小于文献中描述的皮脂腺腺癌。这是一个不寻常的病例，因为肿瘤罕见，而且与文献中描述的皮脂腺腺癌相比，核异型性和侵袭性较低。
