Weber Alfred L, al-Arayedh Sharif, Rashid Asma
Department of Radiology, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA.
Neuroimaging Clin N Am. 2003 Aug;13(3):465-83. doi: 10.1016/s1052-5149(03)00041-8.
NPC represents 0.2% of malignant disease in the white population but is more common in southern China, among Chinese in East Asia and the United [figure: see text] States, and in North Africa, including Saudi Arabia. NPC in these ethnic groups tends to manifest at a younger age. Undifferentiated carcinoma is the most common histopathologic type and is associated with EBV. The tumor is optimally assessed with CT and MR imaging for staging; PET scanning provides optimal assessment of recurrent tumor or small lymph node metastases. The primary tumor in the nasopharynx may be small and infiltrating, causing no or only a small mass effect in the nasopharynx. In these cases, obliteration of fat planes and loss of muscle boundaries are important diagnostic findings, which are best evaluated with MR imaging including, Gd-DTPA with fat suppression. The size of the NPC varies from 1 to 2 cm to large tumors that extend to the oropharynx, PPS, nasal cavities, paranasal sinuses, and orbits. Skull base erosion is independent of the size of the nasopharyngeal tumor and ranges from slight erosion to extensive destruction. A concomitant finding is intracranial invasion, predominantly to the basal cisterns and cavernous sinuses associated with cranial nerve palsies. Intracranial invasion should be assessed with contrast MR imaging. Lymph node metastases in the neck are present in 90% of cases and are bilateral in 50% of cases. In a small percentage of cases, extension of lymph node metastases to the mediastinum and hilar areas are encountered. Distant metastases involve the lungs, skeleton, and liver, and occasionally the choroid. They are usually present at the initial presentation [figure: see text] and increase in frequency in advanced disease and in recurrent tumors. In addition, the metastatic lymph nodes in the neck reveal no specific imaging features that would allow differentiation from other lymph node metastases. They may be discrete, often multiple, and large and bulky displaying a variable degree of necrosis and enhancement following introduction of contrast material. Local recurrence manifests commonly within the first 2 to 3 years posttherapy and is optimally evaluated by MR imaging and PET scanning.
鼻咽癌在白种人群的恶性疾病中占0.2%，但在中国南方、东亚和美国的华裔以及包括沙特阿拉伯在内的北非更为常见。这些种族群体中的鼻咽癌往往在较年轻时出现。未分化癌是最常见的组织病理学类型，与EB病毒有关。对于分期，最佳的评估方法是CT和磁共振成像（MR成像）；正电子发射断层扫描（PET扫描）能对复发性肿瘤或小淋巴结转移灶进行最佳评估。鼻咽部的原发肿瘤可能较小且呈浸润性生长，在鼻咽部不产生或仅产生轻微的占位效应。在这些情况下，脂肪平面消失和肌肉边界不清是重要的诊断依据，通过包括钆喷酸葡胺（Gd-DTPA）脂肪抑制技术的MR成像能最好地进行评估。鼻咽癌的大小从1至2厘米到延伸至口咽、咽后间隙、鼻腔、鼻窦和眼眶的大肿瘤不等。颅底侵蚀与鼻咽部肿瘤大小无关，范围从轻度侵蚀到广泛破坏。一个伴随的表现是颅内侵犯，主要侵犯脑基底池和海绵窦并伴有脑神经麻痹。颅内侵犯应通过增强MR成像进行评估。90%的病例颈部有淋巴结转移，其中50%为双侧转移。在一小部分病例中，会出现淋巴结转移至纵隔和肺门区域的情况。远处转移累及肺、骨骼和肝脏，偶尔也会累及脉络膜。它们通常在初次就诊时就已存在，在晚期疾病和复发性肿瘤中发生率会增加。此外，颈部转移性淋巴结没有可与其他淋巴结转移相鉴别的特异性影像学特征。它们可能是离散的，通常为多个，且体积较大，引入对比剂后显示出不同程度的坏死和强化。局部复发通常在治疗后的头2至3年内出现，通过MR成像和PET扫描能进行最佳评估。
