少见部位神经内分泌肿瘤的影像学表现

The Imaging Features of Neuroendocrine Tumors in the Rare Region

目的分析少见部位的原发性神经内分泌肿瘤(neuroendocrine tumor,NET)的影像学表现,以提高对该肿瘤的认识。资料与方法回顾性分析经病理证实的6例原发性NET的影像学资料,男5例,女1例,年龄51～71岁,平均58岁。肝脏、肾脏、膀胱、肠系膜各1例,胆囊2例。术前4例仅行CT检查,2例行CT和MRI检查。结果 6例中5例属于低分化神经内分泌癌(neuroendocrine carcinoma,NEC),分别位于肝、胆囊、肾及肠系膜,1例膀胱高分化NEC。肝脏原发性NET表现为大肿块伴周边多子灶,肺及腹膜后淋巴结转移,增强后呈不明显环形、分隔状强化。2例胆囊原发性NET分别为肿块型和厚壁型,肿块型1例巨大,随访晚期可见坏死,厚壁型1例黏膜中断,囊壁局限性增厚并肝脏浸润,2例强化均不明显,无腹腔内淋巴结转移。肾脏原发性NET表现为边界清楚的小结节,合并肝多发转移,增强后原发灶及转移灶均轻度强化。肠系膜NET中央坏死,增强后肿块呈轻度环形强化,灶周见肿大淋巴结,邻近肠系膜受牵拉呈"辐射"状。膀胱原发性NET表现为黏膜下密度不均匀结节影,MRI显示中央囊性部分呈长T1、长T2信号;病灶周壁及中间分隔呈短T1、短T2信号,平扫CT上呈稍高密度,增强后病灶呈明显环形强化。结论肝、胆囊、肾脏及肠系膜等少见部位的原发性NET影像表现为大肿块伴中央坏死,境界较清楚,增强后不强化或轻度环形强化或小肿块但早期淋巴结或远处转移。

Objective To discuss the imaging features of primary neuroendocrine tumor（NET） in the rare site,and to improve its diagnostic accuracy.Materials and Methods Imaging data of 6 cases with primary NET proven by pathology were retrospectively analyzed.5 males and 1 female,aged 51 to 71,with an average age of 58.There were 1 case in Liver,kidney,bladder and mesenteric respectively,2 cases in gallbladder.Results 5 cases were poorly differentiated neuroendocrine carcinoma（NEC）,which separately located in the liver,gallbladder,kidney and mesentery,1 case was well differentiated neuroendocrine carcinoma in bladder.Primary NET of Liver showed a large mass with surrounding many small lesions,lung and retroperitoneal lymph node metastasis with no or slghtly circle enhancement.2 cases of primary NET in gallbladder showed mass type and thick wall type,the mass type was huge with necrosis in the central area,the thick wall type showed mucosal disruption and infiltrated the liver,the two cases were not markedly enhanced without lymph node metastasis.Primary NET of renal showed small nodule with clear bound and liver metastasis,the primary tumor and metastatic lesions were all mild enhanced.Primary NET of mesenteric showed central necrosis and soft-tissue radiating from the tumor to adjacent bowel wall with the adjacent lymph nodes enlargement,the mass showed mild ring enhancement.Primary NET of bladder showed uniform nodules under submucosal,the signal of central cyst showed hypointensity on T1 and hyperintensity on T2,while the singal of peritumor and the sepa showed hyperintense on T1 and hyperintensity on T2,the lesion showed slightly hyperdensity on plain CT scan and markedly ring enhancment.Conclusion The imaging features of primary neuroendocrine tumor in the rare site including liver,gallbladder,kidney,bladder were huge tumor with central necrosis,clear margin,no or mild enhancement,or small lesions with lymph node or distant tissue metastasis in the early stage.