【医学英语】乳头状弹性纤维瘤（病例题）
Question：Autopsy of a 70-year-old woman reveals a papillary growth within the left ventricular chamber. The growth consists of a small mass of finger-like projections attached to the mitral valve,without associated valvular or other cardiac abnormalities. Histologically, each papillary
structure is composed of a core of fibrous tissue lined by thickened endothelium. The patient
did not have any history of cardiac disease or evidence of thromboembolism. Which of the
following is the most likely diagnosis?
A. Acute mural thrombus
B. Cardiac myxoma
C. Infective endocarditis
D. Nonbacterial thrombotic endocarditis
E. Papillary fibroelastoma
Explanation: The correct answer is E. Gross and microscopic features of this small mass in the left ventricle are entirely consistent with papillary fibroelastoma. This lesion is not neoplastic,
despite the sound of the name. It probably results from organized thrombi forming on the
endocardial surfaces of the mitral valve or left ventricular cavity. Papillary fibroelastomas
are usually clinically silent and are discovered at autopsy as an incidental finding.
An acute mural thrombus (choice A) would not have a core of fibrous tissue. Acute mural
thrombosis usually develops as a result of stasis in the ventricular cavities, in association
with ventricular enlargement, myocardial infarction, or ventricular aneurysm, for example.
Thrombosis often develops in the atria when there is atrial fibrillation.
Cardiac myxoma (choice B) is the most frequent primary cardiac neoplasm. It is benign and
consists of stellate mesenchymal cells within a myxoid background. Since the left atrium is the
most frequent location, this tumor can produce mitral stenosis by a ball-valve effect.
Both forms of endocarditis are associated with formation of vegetations attached to the surface
of the atrioventricular valves. Vegetations of infective endocarditis (choice C) are bulky and
composed of fibrin, bacteria, and inflammatory cells. Since nonbacterial thrombotic
endocarditis (choice D) is caused by hypercoagulable states, the vegetations consist of
aggregates of fibrin but few inflammatory cells and no bacteria.
Note that all of the above conditions may lead to systemic embolization. Fragments of
vegetations, thrombi, myxoma, and papillary fibroelastoma may detach and be released into the
bloodstream, causing infarcts.
词 汇
papillary adj.乳突的，乳头状突起的，长乳突的;
ventricular chamber [医]心室腔;
mitral valve n.僧帽瓣，二尖瓣;
cardiac adj.心脏（病）的; （胃的）贲门的;n.心脏病患者; 强心剂;
histologically [医]adv.组织学上地，组织结构上地;
endothelium n.内皮，内种皮;
thromboembolism n.血栓栓塞;
endocarditis n.心内膜炎;
hypercoagulable states 高凝状态
ball-valve effect 球阀效应(The intermittent flow of blood in one direction which is blocked in the opposite, a finding classically associated with atrial myxoma)
解析：
问题：一个七十岁女性的尸检显示左心室腔里有一个乳头状肿瘤。这个肿瘤包括一小团附在二尖瓣上的指状突起，无其他相关瓣膜和心脏的异常。组织学上，每一个乳头状的结构由纤维组织构成中心，外膜被以增生的心内膜细胞。此病人无任何心脏病史和血管栓塞的迹象。下列哪项是最有可能的诊断？
急性附壁血栓
心脏黏液瘤
感染性心内膜炎
非细菌性血栓性心内膜炎
乳头状弹性纤维瘤
解释 ：正确答案是E。大体和镜下的特征显示左心室的一小团组织全部是乳头状弹性纤维瘤。尽管名字这样叫，但这种病变不是肿瘤。它可能是由二尖瓣或左心室腔的血栓形成的结果。乳头状弹性纤维瘤通常无临床症状然后在尸检时偶然被发现 。
急性附壁血栓（选项A）不会由纤维组织构成中心。急性附壁血栓的发展通常是由于心室淤滞，例如与心室肥大、心肌梗死、室壁瘤有关。血栓通常会在房颤的时候发生在心房。
心脏黏液瘤（选项B）是发生频率最高的心脏肿瘤。它是良性的，由星状细胞和黏液组成。由于左心房是最常见的发生位置，这种肿瘤可以通过球阀效果产生二尖瓣狭窄。
心内膜炎的两种形式都与房室瓣表面附着的赘生物的形成有关。感染性心内膜炎（选项C）的赘生物体积庞大，由纤维蛋白、细菌和炎性细胞组成。由于非细菌性血栓性心内膜炎（选项D）是由高凝状态引起的，赘生物由纤维蛋白聚合而成，无细菌，炎性细胞少。
注意以上所有的情况都有可能导致全身性栓塞。赘生物、血栓、黏液瘤、乳头状弹性纤维瘤的碎片分离后释放到血液中，导致栓塞。
医学英语栏目：以美国执业医师资格考试（USMLE）为主要推送材料，旨在分享医学词汇及临床病例，提高临床医务工作者的英语学习能力与临床业务水平。