松果体区乳头状肿瘤3例临床病理观察

Clinicopathologic features of papillary tumor of the pineal region: a clinicopathologic analysis of three cases

目的 探讨松果体区乳头状肿瘤的临床病理学特征、诊断和鉴别诊断及预后.方法 收集松果体区乳头状肿瘤3例,常规石蜡切片,行HE染色、免疫组化标记,光镜下观察病理组织学形态及免疫表型特点,并复习相关文献.结果 肿瘤细胞具有上皮性肿瘤特征,有乳头状结构和细胞致密区.在乳头状区域,血管周围被覆多层嗜酸性上皮样肿瘤细胞;在细胞致密区,细胞质透亮或空泡状,局部表现为室管膜分化,可见血管周假菊形团或真菊形团结构,细胞核圆形或卵圆形,染色质点彩状,有明显小核仁.核分裂象2～6个/10HPF,常见坏死灶,微血管增生少见.免疫组化肿瘤细胞CK和CK18（＋）,尤其在乳头状区域呈强阳性;同时vimentin、S-100、NSE和MAP2（＋）;GFAP仅局灶（＋）,EMA呈点状（＋）.Ki-67增殖指数1％ ～3％.结论 松果体区乳头状肿瘤是一类新提出的中枢神经系统神经上皮性肿瘤,组织学以肿瘤的乳头状生长模式为特征,光镜下需与肺、肾转移性乳头状癌、乳头状室管膜瘤、脉络丛肿瘤及乳头状脑膜瘤等鉴别.松果体区乳头状肿瘤容易复发,预后不佳,目前治疗方案不确定.

Objective To investigate the clinicopathological features and prognosis of papillary tumor of the pineal region （PTPR）. Methods Three cases were collected, which were sent for morphologic evaluation using HE stained sections, and immunophenotyping was detected by immunohistochemistry （IHC）, with review of the involved literatures. Results The neoplasm of tumor cells was characterized by epithelioid-appearance showing papillary pattern and cellularity. Perivascular regions were surrounded by multi-layer epithelioid tumor cells with eosinophilic cytoplasm in the area of papillary pattern, whereas the tumor cells exhibiting clear or vacuolated cytoplasm were confirmed in the densely cellular areas, in which foci of ependymal-like differentiation appearing as perivascular pseudo-rosettes and true rosettes may be presented. Round or oval nuclei with stippled ehromatin and distinct nucleolus were confirmed. Mitoses were 2 -6 per 10 high power fields. Isolated necrotic foci were observed while microvascular proliferation was usually absent. PTPR displayed prominent decoration with cytokeratins （pan-CK and CK18）, which was most characteristically seen in papillary structures. Immunostaining showed that the tumor ceils were positive for vimentin, S-100, NSE and MAP2, and focally positive for GFAP with cytoplasmic staining and for EMA with a dot-like pattern. The Ki-67 labeling index was between 1 and 3%. Conclusions PTPR is recently defined as a new neuroepithelial tumor type of the central nervous system. The histological feature of tumor is characterized by the papillary growth pattern that needs to be distinguished from metastatic and primary neoplasms with papillary morphology, including metastatic papillary carcinomas of lung or kidney, papillary ependymomas, choroid plexus papillary tumors and papillary meningiomas. The PTPR is frequently local recurrence with poor prognosis. No definitive treatment strategy exists for PTPR.