摘要： 目的  探讨松果体区中间型滋养细胞肿瘤的临床病理学特征。方法  回顾分析一例松果体区中间型滋养细胞肿瘤患儿的临床诊断与治疗经过，并对手术切除标本进行HE 和免疫组织化学染色，于光学显微镜下观察组织学形态和肿瘤标志物表达变化。结果  患儿为6 岁男孩，临床表现为阴茎增大并生长迅速；MRI检查显示松果体区占位性病变，临床拟诊为生殖细胞瘤。经实验性放射治疗无效后施行外科手术切除。光学显微镜观察肿瘤组织呈大片状坏死，伴大范围钙化和散在新鲜出血，可见实片状、上皮样生长的单核异型性细胞，细胞间相对一致，部分肿瘤细胞围绕血管壁生长并浸润血管壁，细胞质嗜酸性或透明，细胞核呈圆形或不规则形，部分肿瘤细胞核内可见假包涵体，核分裂象罕见；肿瘤细胞高表达广谱细胞角蛋白、CAM5.2、人胎盘催乳素、八聚体结合转录因子3/4、表皮生长因子受体和上皮型钙黏附蛋白；散在表达P53，Ki-67 抗原标记指数约为10%；极少数肿瘤细胞表达人绒毛膜促性腺激素β亚单位；不表达胎盘碱性磷酸酶、甲胎蛋白、CD30（Ki-1）和P63。结论  松果体区中间型滋养细胞肿瘤临床罕见，其组织形态学具有部分胎盘部位滋养细胞肿瘤和部分上皮样滋养细胞肿瘤的特点。治疗原则为放射治疗、手术切除辅助药物化疗。

关键词: 生殖细胞瘤, 滋养层肿瘤, 绒毛膜癌, 松果腺, 免疫组织化学

Abstract: Objective To evaluate the clinicopathological features of intermediate trophoblastic tumor (ITT) in the pineal region. Methods A retrospective study was performed to analyse the diagnostic and therapeutic process of 1 case with ITT in the pineal region. The specimen obtained from the surgery was dealt with common tissue processing mode and cut into slices. HE staining was performed to observe histophathological features. Immunohistochemical staining (SP two-step method) was performed to analyse the expression of tumor markers. Related literatures were reviewed. Results A 6-year old boy with clinical manifestations of penis enlargement and rapid growth for more than one year, presented a mass in his pineal region through MRI. The tumor was surgically excised after it is refractory to 10 times experimental radiotherapy as germinoma. The level of β-human chorionic gonadotropin ( β-hCG) in his postoperative blood was decreased to normal, but gradually increased, once again followed to normal after three times chemotherapy. Patient was normal almost postoperative 6 months later by follow -up. Pathological examination showed sheets necrosis with multiple calcification and scattered fresh blood cells, epithelioid tumor cells with solid growth pattern. The tumor cells were atypical mononuclear cells with relative uniform (between heterotypic cells) and partially surrounding and invasing the vascular walls. The cytoplasm of tumor cells was eosinophilic or clear, the nucleus was round or irregular in shape and some with intranuclear pseudoinclusions, and its mitotic figures were rarely seen under light microscopy. The tumor cells showed strong positive for AE1/AE3, cell adhesion molecules 5.2 (CAM5.2), human placental lactogen (hPL), octamer-binding transcription factor 3/4 (Oct3/4), epidermal growth factor receptor (EGFR) and E-cadherin. P53 was also expressed. The positive rate of Ki-67 was about 10%, and β-hCG was expressed in the extremely tumor cells. The tumor cells were negative for placental alkaline phosphatase (PLAP), alpha-feto protein (AFP), CD30 (Ki-1) and P63. Conclusion ITT in pineal region is very rare, and has partial morphological characteristics of placental site trophoblastic tumors (PSTT) and epithelioid trophoblastic tumors (ETT). This case got a good control through radiotherapy, operation excision combined with chemotherapy.

Key words: Germinoma, Trophoblastic neoplasms, Choriocarcinoma, Pineal gland, Immunohistochemistry