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 【影像诊断】：Scrofula (infectious cervical lymphadenitis) caused by mycobacterium tuberculosis 颈部淋巴结核
【诊断要点】：
- Lymph nodes with centrally diminished (non-fatty) density on CT are abnormal, reflecting either necrosis or tumor infiltration. In an adult they are considered neoplastic until proven otherwise. 淋巴结在CT上表现为中心性密度减低（非脂性）是不正常的，反应坏死或肿瘤侵犯，在成人常常被考虑为肿瘤性，除非被证实为其他。
- In adults, 95% of scrofula cases are caused by mycobacterium tuberculosis, while in children, 90% are caused by non-tuberculous mycobacterium, such as mycobacterium avium intracellulare (MAI). 成人95％的瘰疬性脓肿由结核分枝杆菌引起，而儿童，90％为非结核性的分枝杆菌所引起，如鸟胞内分枝杆菌（MAI）
- Tuberculous lymphadenitis may be unilateral or bilateral and is usually found in Level 2, 3, 4, and 5 nodes.结核性淋巴结炎克雅氏单侧或双侧。
【讨论】：Scrofula, or infectious cervical lymphadenitis, is a term predominantly applied to tuberculous and non-tuberculous mycobacterial infections (NTM) affecting the cervical lymph nodes. Humans are the only reservoir for M. tuberculosis. Other tuberculous bacilli that cause disease in humans are M. bovis, and M. africanum, which most often cause extrapulmonary disease. NTM are ubiquitous, and reside in the soil. They can be found in contaminated water, dairy products, eggs, dust, and even tap water. Approximately 95% of adult scrofula cases are caused by mycobacterium tuberculosis, while the remaining 5% are caused by NTM, such as M avium intracellulare, M scrofulaceum, M kansasii and M chelonei. In children, this statistic is reversed, with NTM responsible for up to 92% of scrofula cases.
成人95％的瘰疬性脓肿由结核分枝杆菌引起，5％为NTM所引起，如鸟胞内分枝杆菌（MAI），M scrofulaceum, M kansasii and M chelonei.在儿童，则恰恰相反，92％以上的瘰疬为NTM所引起
Scrofula produces lymph nodes that are discrete, firm, and typically nontender, in contrast with the lymphadenopathy associated with acute infection that is often tender. A firm mass of matted nodes may become apparent with disease progression, and if untreated, lymphadenopathy can become fluctuant with draining fistulas. Enlarging nodes may compress the esophagus causing dysphagia. The presence of systemic symptoms is variable and more likely in immunocompromised patients.
瘰疬所导致的淋巴结是分散的、坚硬的，通常是无触痛的，而相对应的，由急性炎症所致的淋巴结肿大经常是有触痛。假如不处理，一个粗糙结节构成的肿块可能会出现恶化，肿大的淋巴结可能会出现波动感，伴有瘘道。增大的淋巴结可能会挤压食管引起吞咽困难。全身性症状不一定会出现，往往见于免疫缺陷患者。
Scrofula presents with a variable imaging appearance depending upon the stage of the disease. Tuberculous lymphadenitis may be unilateral (90% in adults) or bilateral and is usually found in the internal jugular nodal chains (levels 2 - 4) and the spinal accessory chains (levels 5a and 5b). In the early infectious phase, non-necrotic nodes have homogeneous signal intensity and enhance homogeneously with contrast on both CT and MR. As the disease progresses and nodes become necrotic, CT images demonstrate characteristic central low density, representing necrosis, with a thick rim of enhancement. Peripheral contrast enhancement reflects hyperemia of the inflamed lymph node capsule or increased lymph node vascularity. On MR images, the necrotic center of the nodes will show intermediate signal intensity on T1-weighted images, low signal intensity on T2-weighted images, and will enhance with contrast. The surrounding granulation tissue, with its inflammatory hypervascularity and increased vascular permeability, will be markedly hyperintense on T2-weighted images. The nodes may become multiloculated and matted, simulating metastatic cervical disease both on imaging and clinically. Despite extensive necrosis, infiltration of adjacent fat planes is minimal, which may differentiate this process from other infections or malignant nodal disease. Chronic or post-treatment nodes are characterized by fibrous and calcific elements that are easily identified on CT. Calcification can also be seen in scrofula caused by NTM. On MR, treated nodes are homogeneously hypointense on both T1 and T2-weighted images, and do not enhance with contrast.
根据病变所处的不同时期，颈部淋巴结结核表现为不同的影像改变，结核性淋巴结炎可以是单侧（在成人达90％）或双侧，并且通常见于颈内淋巴结链（第2-4级）和脊髓副链（5a和5b）。在早期，非坏死性的淋巴结炎无论在CT或MRI上都表现为均匀的信号强度和均一的强化。随着病变的进展，淋巴结出现坏死，CT上表现为特征性的中央低密度，代表坏死，伴有增厚的环状强化。外周的强化反应了炎性的淋巴结包膜的充血或淋巴结血供的增多。MR影像上，在T1序列上中央坏死显示中度强度的信号，T2序列上呈低信号，增强扫描有强化。周边的肉芽组织，由于炎性的富血供和血管通透性的增高，导致在T2序列上显示为明显的高信号。肿大的淋巴结可能表现为多房状，表面粗糙，无论是影像上还是临床上都类似于转移性的病变。尽管有广泛性的坏死，但是邻近之脂肪间隙的渗透几乎没有，这可能可以帮助鉴别其他的炎性或恶性的淋巴结肿大。慢性或术后的淋巴有纤维化或钙化的成分，这在CT上可以很好的被鉴别。钙化也可以见于有NTM所引起的瘰疬.在MRI上，治疗后的淋巴结无论是T1或T2序列上都表现为均匀的低信号，而且没有强化。
Cervical lymph nodes enlarge in response to neoplastic, inflammatory, and systemic disease. The broad differential diagnosis of enhancing cervical lymphadenopathy in an adult includes, but is not limited to, metastatic squamous cell carcinoma, metastatic papillary thyroid carcinoma, lymphoma, tuberculous and nontuberculous mycobacterial lymphadenitis, cat-scratch disease, Kaposi sarcoma, AIDS-related lymphadenopathy, acute septic infection, Kimura disease, Castleman disease, and Kikuchi disease. Fungal infections and viral infections, such as Epstein-Barr virus, herpes simplex virus, cytomegalovirus, and rubella also may present with bilateral diffuse lymphadenopathy.
Diagnosis usually requires fine needle aspiration (FNA) for histologic examination and culture. Once scrofula is diagnosed, it is important to determine the exact etiology, as tuberculous scrofula is treated medically and NTM infections are treated surgically. Lymphadenopathy may initially worsen during antituberculous therapy, representing an immune response to killed mycobacteria. Surgical intervention is reserved for complications such as abscess formation and draining sinuses. The treatment of choice for NTM infections is complete surgical excision of all affected tissue.
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