探讨耳后淋巴结内涎腺透明细胞型嗜酸性腺瘤的诊断学特征。

回顾性分析2022年1月21日联勤保障部队第928医院五官科收治的1例耳后淋巴结内涎腺透明细胞型嗜酸性腺瘤患者的临床及病理资料，结合文献，总结其诊断学特征。

患者女性，15岁，3年前发现左耳后肿物，约"花生米"大小，后增大至"鹌鹑蛋"大小；查体发现左耳后皮下触及一肿物，质地中等，边界清，活动度一般。彩超提示左侧耳后实性占位，大小约3.3 cm×2.8 cm，边界清，内回声不匀，双侧腮腺及甲状腺未见异常。胸腹部CT检查均未见异常。左耳后肿物摘除术中见肿物位于耳后皮下淋巴结群位置，距离左侧腮腺约0.5 cm。术后病理大体检查示肿物大小4.0 cm×3.2 cm×2.6 cm，表面灰红及黄白色，不规整椭圆形，有完整包膜，切面灰黄灰白，质偏软。HE染色示纤维包膜内主要为腺泡状密集增生的嗜酸性上皮细胞、透明细胞及泡沫样细胞，包膜边缘可见残余的淋巴组织间隙；瘤细胞核中位，核仁及核分裂象少见，胞质丰富。免疫组织化学染色结果示广谱型细胞角蛋白(CK)阳性，高分子量细胞角蛋白(HCK)少量阳性，低分子量细胞角蛋白(LCK)阳性，P63、S-100、平滑肌肌动蛋白(SMA)、波形蛋白 (Vimentin)、肾细胞癌标记物(RCC)、甲状腺球蛋白(TG)、P53、雌激素受体(ER)、孕激素受体(PR)、癌胚抗原(CEA)、Dog-1蛋白(Dog-1)、人表皮生长因子受体2(Her-2)、糖类抗原125(CA125)、甲状腺转录因子-1(TTF-1)均阴性，Ki-67核蛋白(Ki-67)阳性率1%~2%。病理诊断为左耳后淋巴结内涎腺透明细胞型嗜酸性腺瘤。

耳后淋巴结内可发生嗜酸性腺瘤，其发生可能与淋巴结内涎腺异位有关；与涎腺内原发嗜酸性腺瘤相比，呈年轻化特点，并有透明细胞变特征；该肿瘤的诊断需紧密结合临床表现、组织学特征和免疫组织化学特点进行鉴别排除。

To explore the diagnostic features of clear cell type oxyphilic adenoma of salivary gland in retroauricular lymph nodes.

The clinical and pathological data of a patient with clear cell type oxyphilic adenoma of salivary gland in retroauricular lymph node admitted to the Department of Otorhinolaryngology, the 928th Hospital of the Joint Support Force on January 21, 2022 were retrospectively analyzed, and the diagnostic characteristics were summarized combined with literature.

A 15-year-old female patient presented with a mass behind her left ear 3 years ago, whose size initially was like a " peanut" and subsequently enlarged to the size of a " quail egg". Physical examination found that the neoplasm was under the subcutaneous layer of the left ear, medium in texture, clear in boundary, and average in motion. Color Doppler ultrasound showed a solid mass, about 3.3 cm×2.8 cm in size, with clear boundary and uneven internal echo. There were no abnormalities in the bilateral parotid glands and thyroid glands. Chest and abdominal CT examinations showed no abnormalities. During the operation, it was found that the mass was located in the subcutaneous lymph node group behind the ear, about 0.5 cm away from the left parotid gland. Postoperative pathological examination showed that the tumor size was 4.0 cm×3.2 cm×2.6 cm, with a gray-red and yellow-white surface, irregular oval, complete capsule, a gray-yellow and gray-white section, and soft texture. HE staining showed eosinophilic epithelial cells with dense acinar proliferation, clear cells and foamy cells within the fibrous capsule, with residual lymphoid tissue space at the edge of the capsule. The nuclei of the tumor cells were centrally located, with few nucleoli and rare mitotic figures. The cytoplasm was abundant. Immunohistochemical staining showed positive for broad-spectrum cytokeratin (CK), a small amount of high weight molecular cytokeratin (HCK), and low weight molecular cytokeratin (LCK), while negative for P63, S-100, smooth muscle actin (SMA), Vimentin, renal cell carcinoma (RCC) marker, thyroglobulin (TG), P53, estrogen receptor (ER), progesterone receptor (PR), carcinoembryonic antigen (CEA), discovered on GST-1 protein (Dog-1), human epidermal growth factor receptor 2 (Her-2), carbohydrate antigen 125 (CA125), thyroid transcription factor-1 (TTF-1). The Ki-67 nucleoprotein positive rate was 1%-2%. The pathological diagnosis was a clear cell type oxyphilic adenoma of salivary gland in retroauricular lymph nodes.

The oxyphilic adenoma can occur in the lymph nodes located behind the ear, which may be related to heterotopic salivary glands in lymph nodes. It displays younger age and cell hyaline degeneration when compared to primary oncocytoma in the salivary gland. The clinical signs, histological traits, and immunohistochemical properties of this tumor must be meticulously coupled to make a diagnosis.