纵隔原发精原细胞瘤的临床及影像学特征

Primary mediastinal seminoma:imaging features correlated with clinical findings

目的探讨纵隔原发精原细胞瘤的临床和影像学特征。方法回顾性分析2012年4月至2017年2月江苏省肿瘤医院收治的13例经病理组织学证实的纵隔原发精原细胞瘤患者的临床、病理及影像资料,观察临床病理特点和病变影像学特征。结果 13例患者均为男性,中位年龄35岁;血清AFP均未增高,其中7例血清β-HCG增高。影像学检查发现13例肿瘤部位均位于前纵隔,肿块>5 cm 12例,形态不规则12例。13例患者CT平扫呈软组织密度,伴有钙化4例;CT增强扫描呈较均匀轻度强化,肿块内见小片状低密度影;12例呈现心包大血管包绕侵犯,2例肺门淋巴结肿大。4例MRI检查表现为肿块呈稍长T_1稍长T_2信号。3例行手术切除,11例行肿块穿刺活检,首次穿刺活检常规病理检查误诊5例,经手术明确诊断1例,重新切片或活检并加做免疫组化明确诊断4例。结论纵隔原发精原细胞瘤患者的性别、发病年龄、血清标志物及影像表现均有一定的特征性,部分穿刺活检常规病理易误诊,结合临床、实验室检查、影像学表现及进一步免疫组化检查有助于明确诊断。

Objective To investigate the appearance of primary mediastinal seminoma on CT and MRI correlated with clinical features.Methods From April 2012 to February 2017 in Jiangsu Cancer Hospital,pathological characteristics and imaging findings of13 patients with histopathological proven mediastinal seminoma were retrospectively reviewed and analyzed.Results All of the 13 patients were male and the median age was 35 years,among whom 7 patients were tested with elevated β-HCG,13 cases were tested with negative AFP.Thirteen cases of mediastinal seminoma were all located in the anterior mediastinum including 12 cases bearing irregular masses,and 12 masses were greater than 5 cm.Thirteen masses revealed homogeneous attenuation on non-enhanced CT images and showed homogeneous and slight enhancement after contrast administration with small areas of low density,and 4 masses with stippled calcification.Tumors encircling macrovasular were found in 12 cases,and hilar lymphadenophathy were identified in 2 cases.The masses appeared slightly hypointense on MRI T_1 WI and slightly hyperintense on T_2 WI（SPAIR）.Among the 13 patients,3 cases were with complete resections,while 11 cases underwent biopsies,and 5 cases of them were misdiagnosed.One patient was diagnosed by surgery and four patients were diagnosed depending on pathological section again or repeated biopsy,and immunohistochemical analysis.Conclusion The gender,age of onset,the serum levels of tumor markers and imaging findings of primary mediastinal seminoma have certain characteristics.CT-guided percutaneous biopsy is the cause of misdiagnosis sometimes,so final diagnosis depends on clinical feature,serum levels of tumor markers,image findngs and further immunohistochemical analysis.