Is it benign or malignant? Imaging lymph nodes: a pictorial review of imaging findings. Poster No.:

C-0701

Congress:

ECR 2011

Type:

Educational Exhibit

Authors:

J. M. García Gómez, R. M. Lorente-Ramos, J. Azpeitia Arman, M. Grande-Barez, A. Munoz Hernandez, P. Díez Martínez; Madrid/ES

Keywords:

Metastases, Inflammation, Infection, Imaging sequences, Ultrasound, MR, CT, Lymph nodes, Head and neck

DOI:

10.1594/ecr2011/C-0701

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Learning objectives

Fig. References: J. M. García-Gómez; Department of Radiology, Unidad Central de Radiodiagnóstico de la CAM. Hospital Infanta Leonor, Madrid, Spain. To analyse imaging findings in normal and pathologic SUPERFICIAL LYMPH NODES in several imaging modalities (US, CT and MR) correlated with histopathologic findings when available. To illustrate a wide spectrum of pathologic disorders affecting lymph nodes. To emphasize pitfalls, diagnostic difficulties and differential diagnoses of these entities.

Images for this section:

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Fig. 1

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Background

We review the distribution of SUPERFICIAL LYMPH NODES: neck, axilla and inguinal region. We analyse morphologic criteria in normal and pathologic nodes: size, internal architecture, necrosis, number, specific (silicone) and associated findings (neoplasm). We illustrate the US, Doppler, CT and MR findings in reactive lymph nodes (bacteria, virus, syphilis, tuberculosis, Kikuchi disease and amyloidosis) and tumors (lymphoma and metastases). We review the role and procedure of ultrasound-guided interventional (fine-needle aspiration and core needle biopsy).

Table of contents Images for this section:

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Fig. 1

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Fig. 2

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Fig. 3

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Imaging findings OR Procedure details

Fig. References: J. M. García-Gómez; Department of Radiology, Unidad Central de Radiodiagnóstico de la CAM. Hospital Infanta Leonor, Madrid, Spain.

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Fig. References: J. M. García-Gómez; Department of Radiology, Unidad Central de Radiodiagnóstico de la CAM. Hospital Infanta Leonor, Madrid, Spain.

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Fig. References: J. M. García-Gómez; Department of Radiology, Unidad Central de Radiodiagnóstico de la CAM. Hospital Infanta Leonor, Madrid, Spain.

INTRODUCTION

Physical examination is essential in detecting superficial lymph nodes (Figure 4 on page 26), but there is an important percentage no detectable on palpation. Thus, imaging is safe to know these hidden nodes and its characteristics that help determine the benign or malignant nature. Moreover, the identification of nodal metastases is of prime importance in the staging of cancers (prognostic factor) for proper planning treatment.

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ANATOMY

1. Cervical nodes: Almost 40% of all nodes in the body are above the clavicle. Cervical nodes are classified into different levels based on anatomy and the image obtained on CT. This classification has been adopted by the American Joint Committee on Cancer and provides seven levels (Figure 5 on page 27 and Figure 6 on page 28) from the floor of the mouth and the skull base to the clavicles. Level I nodes extends between the floor of the mouth and the lower edge of the hyoid bone and between the mylohyoid muscle and the posterior edge of the submandibular gland. The anterior belly of the digastric muscle divides this space into Ia and Ib, the first one including the submental nodes and the second one the submandibular nodes. Level II extends from the skull base to the hyoid bone, between the submandibular gland and the posterior edge of sternocleidomastoid muscle. Level III nodes lie between the hyoid bone and the lower margin of the cricoid cartilage and extending between either the common carotid artery or the internal carotid artery and the posterior edge of sternocleidomastoid muscle. Level IV includes all nodes between the cricoid cartilage and clavicle with the same anterior and posterior landmark than level III. Levels II, III and IV nodes are the nodes of the internal jugular chain. Level V represents the nodes of the posterior cervical triangle, which extends from skull base to the clavicle and from the sternocleidomastoid muscle to the anterior edge of the trapezius muscle. Level VI covers the space defined between the hyoid bone and the top of the manubrium and between both common carotid arteries and internal carotid artery. They are the visceral nodes. Level VII nodes are the superior mediastinal nodes, framed between the upper margin of the manubrium, the innominate vein, and the left and right common carotid arteries.

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Parotid and supraclavicular nodes are excluded from this classification. The latter are located lateral to the carotid arteries, at the height of both clavicles, above the top of the sternal manubrium.

2. Axillary nodes: Axillary nodes are below the clavicle and lateral to the ribs and they are responsible for the drainage of lymphatic vessels from the breast, the thoracoabdominal wall above the level of the umbilicus, and from the upper limb. Most authors recognize three node levels relative to the pectoralis minor muscle: Level 1, nodes located below the lateral margin of the pectoralis minor muscle. Level 2, nodes located behind the pectoralis minor muscle. Level 3, nodes located above the medial margin of the pectoralis minor muscle (subclavicular nodes).

3. Inguinal nodes: They are divided into superficial and deep nodes: The superficial nodes are arranged in the area of the triangle of Scarpa in a vertical and a horizontal group, the first ones accompanying the great saphenous vein and the second ones accompanying the inguinal ligament. Deep nodes lie along the inner edge of the femoral vein. The superior-most lymph or node of Cloquet occupies the innermost portion of the femoral ring. Inguinal nodes drain into the external iliac nodes and then to the common iliac nodes.

MORPHOLOGICAL CRITERIA

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Imaging modalities contribute with features used as normal parameters or disease indicators that help us to recognize signs of benign or malignant disease, or even to make a differential diagnosis. The size and architecture are the two main parameters in the assessment of lymph nodes.

1. Size and shape: Normal nodes are ovoid (Figure 7 on page 29). When a node is enlarged, it often adopts a round morphology. Therefore, these two criteria are closely related. They are considered good indicators of pathology, but not reliable to differentiate benign or malignant disease. A round node is abnormal, but it may be due either to an inflammatory or a neoplastic cause. The size depends on the nodal region: a threshold accepted by most of the series is 10 mm (5 mm in the supraclavicular) in the short axis in its maximum diameter.

2. Internal architecture: A normal node has a thin cortex and a central fatty hilum (Figure 7 on page 29). The presence of the hilum is highly indicative of non-metastatic nodes. When there is an eccentric cortical thickening or bulging and a diminished or absent hilum these are proper findings to consider. In this regard, ultrasound (US) or computed tomography (CT) reflects a hypoechoic or hypoattenuating node, respectively. Due to the lower spatial resolution of CT, its sensitivity to assess the hilum is lower.

3. Necrosis: Usually, necrosis is central and proportional to the node size, but it is considered a pathological finding regardless of size. The first area invaded by tumor cells is the subcapsular one, and thus, US and CT can find a hypoechoic or hypoattenuating focus in the periphery of the node (Figure 8 on page 30).

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Necrosis is more typical of the cervical region and the most common causes are infection and metastasis of head and neck cancers(Figure 9 on page 31 and Figure 10). This finding can also occur in other malignancies such as papillary thyroid carcinoma, non-Hodgkin´s disease (Figure 11 on page 33 and Figure 12),…, or even urothelial carcinoma (Figure 8 on page 30).

4. Number: A node group consider pathological with more than three borderline size nodes. This feature can be seen in inflammation, carcinoma or lymphoma.

5. Calcifications: Superficial node calcification is rare, but its mere presence is a marker of nodal disease, whether active or a sequela of previous illness. They have the advantage of limiting the differential diagnosis and they are well detected on US. They are classified into coarse, related to a prior inflammatory disease (especially tuberculosis) or lymphoma treated with chemotherapy or radiotherapy (indicative of good response), and punctate, found in metastases from papillary thyroid carcinoma.

6. Other parameters: Extracapsular extension with amorphous and ill-defined margins nodes indicates spread outside. Invasion of vascular structures is a relatively common finding of the internal jugular nodes, especially infiltration of the common carotid artery or internal carotid artery. The invasion of the internal jugular vein is also a sign of poor prognosis, but unlike the previous one, does not condition treatment (Figure 8 on page 30).

IMAGING STUDIES

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Usually, US and Doppler are the first imaging method to be performed. However, the modality of initial study depends on the hospital and must be agreed in a multidisciplinary manner with other specialties.

1. Ultrasound: US have a high spatial resolution and characterize best the hilum. It is also the most sensitive technique for the visualization of calcifications. US basically evaluate the size, internal architecture and number.

2. Doppler: It is a good complement to US and allows a reliable assessment of the node parenchyma. The color Doppler shows a radial vascular distribution from the centred hilum. A nonhilar peripheral flow (subcapsular vessels) is a clear sign of pathology, probably related to metastatic disorder or reactive nodes (tuberculosis), as a result of angiogenesis. Lymphomas, however, usually have no alteration on the Doppler. In this regard, the power Doppler is more sensitive in detecting signs of flow than the color Doppler. Spectral Doppler can assess the resistive index and pulsatility index. When values are above 0.8 or 1.5, respectively, almost always responds to metastasis.

3. Computed tomography: CT is widely accepted as the imaging method of choice in the staging of head and neck cancers. Lately, it has been defended its combined use with Doppler for the detection of metastatic nodes. The evaluation should be made in two planes (axial and coronal). Its sensitivity decreases due to artifacts caused by metallic dental material. Like US, it values the nodal size, architecture, and especially necrosis, based on the attenuation and type of enhancement after the injection of contrast material. Heterogeneous, marked focal or ring of peripheral enhancement, and hypoattenuating area are abnormal findings.

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4. Magnetic resonance: The great advantage of magnetic resonance (MR) is its multiplanar capability and the assessment of soft tissue, helping for instance in the determination of extranodal extension (Figure 9 and Figure 10 on page 32). MR imaging must include a fat-suppressed T2 weighted sequence, or STIR sequence in their absence, and a T1 weighted with fat suppression after gadolinium administration (Figure 11 and Figure 12 on page 34). A heterogeneous or hypointense area without gadolinium enhancement on T1 weighted and a heterogeneous or hyperintense area on T2 weighted are revealing. The apparent diffusion coefficient (ADC), obtained from the diffusion weighted sequences, provides functional information that distinguish benign lymph nodes from metastases and from lymphomas. The ADC is a marker of cell density. Thus, it is lowest in lymphoma and highest in metastatic nodes.

NODAL PATHOLOGY

1. Cervical:

Reactive lymphadenitis: Reactive lymphadenitis is common, especially in children. They are derived from pharyngitis or tonsillitis, but also otitis, mumps,... US is the main imaging method, where usually hypoechoic adenopathy are seen, but with retained central hilum (Figure 13 on page 35). Sometimes, the typical architecture is lost and nodes are less well defined (Figure 14 on page 36). Acute bacterial suppurativle lymphadenitis is usually very painful, as opposed to tuberculous adenitis. It is characterized by a necrotic centre: hypo or anechoic with solid peripheral aspect on US, hypoattenuating with ring enhancement on CT (Figure 15 on page 37) and variable appearance on T1 and T2 weighted MRI according to the protein content. Nodes may have coalesced and multiloculated cystic appearance (Figure 16 on page 38).

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Cervical tuberculous lymphadenitis, also known as scrofula, is a frequent expression of extrapulmonary tuberculosis and accounts for 5% of cases of cervical adenopathy. Typically, tuberculosis affecs young adults bilaterally, especially the posterior cervical triangle and supraclavicular nodes (Figure 17 on page 39). On CT, the affected nodes have a hypoattenuating centre (represents caseation necrosis) and peripheral enhancement (Figure 18 on page 40). They can also adopt variable patterns depending on the natural history of illness: homogeneous in attenuation (initial phase), coalescence of nodes with an enhancing rim and an irregular thickness (progression disease) or a calcified appearance (acquired after healing). Sometimes complications occur such as inflammation of soft tissue, abscesses or sinuses adjacent to the node margins (Figure 18 on page 40). When a lymphadenitis persists or progresses despite antibiotic treatment, other possibilities should be assessed such as toxoplasmosis, mononucleosis, cat scratch disease or non-tuberculous mycobacteria.

Metastases: Squamous cell carcinomas are the most frequent tumors of head and neck tumors. Cervical nodes are the natural drainage path, in particular, cancers of the tongue (Figure 9 and Figure 10), floor of mouth, pyriform sinus and supraglottis. Central nodal necrosis and extracapsular infiltration are findings often observed in metastatic cancers of the head and neck. It may be difficult to differentiate from a tuberculous scrofula or an abscess. Patient history is helpful to distinguish between these entities. Within the larynx, the supraglottic (Figure 19 on page 41) account for 30% of cases. The diagnosis is late because there is no hoarseness (not affecting the vocal cords) and often present with early nodal metastases. Glottic cancers, however, are diagnosed early and rarely have nodal metastases (the vocal cords are alymphatic). Nasopharyngeal cancers are among the unknown primary tumors, that initially present as lymphadenopathies (Figure 20 on page 42). Supraclavicular nodes deserve special mention. Most palpable nodes are usually affected by metastases. Therefore, US and CT are important in their detection. Lung (Figure 21 on page 43) and esophagus cancers are closely related to these nodes,

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but can also metastasize breast, prostate (Figure 22 on page 44), gynecological, stomach and pancreas cancers.

Lymphoma: Lymphoma represents the second cervical malignancy in frequency. Nodes most involved are the internal jugular and the accessory spinal. The typical presentation (Figure 23 on page 45) are rounded, large, homogeneous (hypoechoic on US and isoattenuating to muscle on CT) and bilateral nodes. Sometimes, the affectation is very extensive and confluent. The necrosis is rare, suggesting then a non-Hodgkin´s lymphoma of high grade (Figure 11 and Figure 12). There are distinguishing features between Hodgkin´s disease and non-Hodgkin´s lymphoma. In the first, the extranodal involvement is uncommon (Figure 11 on page 33 and Figure 12), while the latter typically involves extranodal structures in the head and neck such as the Waldeyer tonsillar ring, paranasal sinuses and nasal cavity. The main differential diagnosis is metastasis from squamous cell carcinomas of the head and neck. The suspicion is founded when we meet with bilateral nonnecrotic nodes in unusual sites for squamous cell carcinomas, including submental, submandibular and posterior cervical triangle nodes.

Kikuchi disease: Kikuchi disease is a benign reactive lymphadenitis, also known as necrotizing lymphadenitis, as histologically is characterized by cortical necrosis. It mainly affects young women with unilateral cervical lymphadenopathy and fever (30-50%). Normally, nodes affect levels II-V, do not exceed three centimetres and homogeneously enhance without or with necrosis on CT (Figure 24 on page 46). The disorder spontaneously resolves within few months and it is difficult to differentiate, even clinically and histologically, from lymphomas (Figure 25 on page 47). In this way, a follow-up CT may be helpful.

Amyloidosis:

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Amyloidosis is a group of diseases resulting from extracellular deposition of different proteins that form amyloid. There are two clinical forms: localized amyloidosis (10-20%) and systemic amyloidosis (80-90%), which is subclassified into an idiopathic or primary (AL), a secondary or reactive (AA) and familial (AF) form. Nodal amyloidosis (Figure 6 on page 28) is rare (less than 20% of cases). Typical findings are multiple enlarged and bilateral nodes, and more rarely, speckled or eggshell calcifications. The systemic form can affect multiple nodal territories (cervical, axillary, mediastinal, retroperitoneal and inguinal), making it difficult the differential diagnosis with lymphoma. We must also take into account the possibility of sarcoidosis or metastases.

PITFALLS Patient 1: 44 year-old man, that presents on physical examination a cavum hypertrophy, almost obstructing the choanae, and right adenopathy at level II. Cavum biopsy is performed, with no evidence of malignancy. It was decided to perform adenectomy.

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Fig.: US shows hypoechoic, ovoid, slightly heterogeneous and absent hilum nodules. They are compatible with nodal metastases and are located adjacent to submandibular gland. References: J. M. García-Gómez; Department of Radiology, Unidad Central de Radiodiagnóstico de la CAM. Hospital Infanta Leonor, Madrid, Spain. Diagnosis: Warthin tumor (cystadenolymphoma).

Patient 2: A 68 year-old woman with a history of right nephrectomy 10 years ago by clear cell adenocarcinoma browses by right cervical lymph node 4 months duration, partially adhered to deep planes. It performs excision of the node.

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Fig.: US reveals hypoechoic nodule slightly vascularized in submandibular location. Hilum is not identified. CT shows a hypoattenuating nodule located posterior to submandibular gland with fat plane of cleavage. It is compatible with nodal metastases. References: J. M. García-Gómez; Department of Radiology, Unidad Central de Radiodiagnóstico de la CAM. Hospital Infanta Leonor, Madrid, Spain. Diagnosis: Schwanoma.

2. Axillary: Reactive lymphadenitis: See section of the neck. Tuberculosis has had an increase in its prevalence in both immunocompetent population and immunocompromised patients. It can affect any organ or system. Tuberculosis in

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the axilla is not very common (Figure 26 on page 48), but it must be known for its increase in incidence discussed above.

Metastases: Axillary nodes are the main lymphatic drainage of the breast. Thus, nodal metastases of breast carcinoma are the most common malignant disease of the axilla. Typically, the primary lesion is evident on mammogram or palpation (Figure 27 on page 49). Lymph node involvement from breast carcinoma is rare if intramammary malignancy is not observed (Figure 28 on page 50). In these cases, most probably it will be a lymphoma or chronic lymphocytic leukemia, especially if nodes are bilateral and homogeneously dense. However, it is necessary to for a hidden breast lesion and a MR with gadolinium is recommended. Other malignancies such as lung cancer, thyroid or melanoma, may present with axillary lymph node metastases. Chronic lymphocytic leukemia (Figure 29 on page 51) should be included in the differential diagnosis of axillary lymph node malignancy. Nodal involvement is usually bilateral.

Lymphomas: 40% of patients with non-Hodgkin lymphoma and 25% of Hodgkin's disease have axillary node involvement. Proper staging is important to design the treatment. Axillary lymphomas (Figure 25 on page 47) shows the characteristics already described in the cervical region.

Silicone adenopathy: Silicone is a nonbiodegradable biocompatible material, with many cosmetic and therapeutic applications. It can induce a local foreign body reaction or distally, if silicone droplets migrates.

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The silicone adenopathy is a recognized complication of breast implants (Figure 30 on page 52) and orthopedic joint replacements. The typical findings are extremely dense nodes on mammography, which can be mistaken for metastatic breast carcinoma, and hyperechoic with preserved vascularization on US.

3. Inguinal: Reactive lymphadenitis: See the corresponding section of the cervical nodal disease, making an exception, the source of many of these is the genitourinary pathology. The major example is the syphilis: The primary chancre of the genitalia is often associated with inguinal painless nonsuppurative nodes, predominantly unilateral (Figure 31 on page 53), which can persist for months. In secondary syphilis, lymphadenopathies are generalized.

Lymphomas: It is fundamental assessment of all possible nodal chains. Thus, the inguinal nodes may also be affected. We must remember the association with AIDS. These lymphomas are characterized by non-Hodgkin lymphoma with of high grade B-cell phenotype, aggressive clinical course and extranodal involvement. A typical aspect of all lymphoma is bulky adenopathies that displace, trap and narrow the vessels but does not infiltrate. This is the case with our patient (Figure 32 and Figure 33).

Metastases: Inguinal nodes are the first station from primary cancers of the lower part of the vagina, vulva, penis (Figure 34 on page 56), lower part of the rectum, anus, and lower extremities. In addition, we must consider other pelvic cancers.

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ULTRASOUND-GUIDED INTERVENTIONS

The fine-needle aspiration and core needle biopsy are simple and reliable procedures for the diagnosis of nodal metastases when they are used together with US and Doppler, which should be included in diagnostic protocols, as it happens in our Hospital. In addition, US is able to differentiate large collections in suppurative lymphadenitis and to guide its drainage.

Images for this section:

Fig. 1

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Fig. 2

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Fig. 3

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Fig. 4

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Fig. 5

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Fig. 6: Male 74 year-old under study for cervical lymphadenopathies. CT confirmed nodes in all anatomical levels. Significant compression of both internal jugular veins.

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Fig. 7: Echoic central hilum and radial vascularization.

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Fig. 8: 66 year-old man with four resections of bladder cancer. Inguinal node with peripheral hypoechoic foci (white arrows). The extension study reveals right jugular node (encasement common carotid artery, yellow arrow) and left (hypoattenuating centre, red arrow).

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Fig. 9: 62 year-old smoker and drinker man. Nodes with hypoechoic and very hypoattenuating areas related to necrosis.

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Fig. 10: MR of the same patient shows level II and IV nodes with hypointense areas of necrosis. One node contacts but no invading internal carotid artery.

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Fig. 11: 68 year-old smoker man with dysphonia and cervical nodes. US shows multiple bilateral nodes, some necrotic. CT reveals a circumferential mass cavum and cervical nodes.

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Fig. 12: MR of the same patient shows massive level II, III and IV and supraclavicular nodes with necrosis on STIR sequence and enhanced-contrast sequence.

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Fig. 13: 3 year-old boy with persistent nodes were serologically positive for adenovirus and CMV. It was appreciated central hilum and vascularization on US.

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Fig. 14: 18 month-old girl with fever and erythema. US shows inhomogeneous with illdefined edges left cervical and supraclavicular nodes and MR hyperintense nodes on STIR sequence.

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Fig. 15: 37 year-old man with sore throat and cervical tumor. CT shows a very hypoattenuating node with ring enhancement. In subsequent checks, it was confirmed an adenophlegmon.

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Fig. 16: 2 year-old girl with hard, painful and hot laterocervical tumor. US shows a left parotid gland with increased size and vascularity, suggestive of mumps. Also, there is a dominant heterogeneous node, probably with abscessification, confirmed a week later.

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Fig. 17: 69 year-old woman with constitutional syndrome and supraclavicular and mediastinal nodes. US confirmed bilateral supraclavicular nodes, most with eccentric hilum and hypoechoic area suggestive of avascular necrosis (see image). CT reveals a hypoattenuating node. Note the difficulty of distinguishing between the caseous necrosis and the necrosis of a malignant disorder.

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Fig. 18: 36 year-old man with painless to palpation right laterocervical tumor. CT reveals level IV (anterior displacement of the jugular vein) and V (hypoattenuating centre) nodes and superficial soft-tissue involvement (red arrows).

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Fig. 19: 78 year-old ex-smoker man with right laterocervical tumor. US shows a hypoechoic mass at level III and CT a node with necrotic areas and significant compression of internal jugular vein. Note the primary neoplasm of supraglottis.

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Fig. 20: 52 year-old man with painless to palpation right laterocervical tumor. Level IV node with anterior displacement of supraaortic trunks is seen on CT. Right radical neck dissection is performed without known primary cancer.

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Fig. 21: 70 year-old man with constitutional syndrome and suspicion of superior vena cava syndrome. Multiple mediastinal and supraclavicular conglomerate mass of right nodes are seen on US and CT.

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Fig. 22: 69 year-old man with left supraclavicular mass. In addition, the CT found mediastinal and retroperitoneal nodes. The differential diagnosis included lymphoma.

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Fig. 23: Typical homogeneous round nodes of lymphoma, Hodgkin (right image) or nonHodgkin (left image).

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Fig. 24: 24 year-old woman with right cervical tumor at level II. Many laterocervical nodes are seen at different levels, hypoechoic with preserved hilum on US (yellow arrow) and homogeneous on CT, one hypoattenuating (red arrow), suggesting necrosis.

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Fig. 25: Male 17 year-old, initially diagnosed as Kikuchi disease. He returns to check for right axillary node. US reveals a loss of hilum node and CT a dominant node displacing anteriorly pectoral muscles and posteriorly axillary vein.

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Fig. 26: 75 year-old woman with left axillary tumor and fistula. CT (first imaging study performed) shows significant node by size and number. US (complementary to mammogram) reveals very hypoechoic nodes, one fistulized to skin.

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Fig. 27: 41 year-old woman with axillary nodules. US shows very hypoechoic nodes with hilar loss, clearly suspicious of malignancy. It scans left breast revealing polilobulated nodule. The fine-needle aspiration and core needle biopsy confirmed infiltrating ductal carcinoma.

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Fig. 28: Screening mammogram reveals radiodense axillary nodes, which are confirmed by US and MR, but without finding the primary tumor.

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Fig. 29: Bilateral axillary nodes on palpation. Mammogram shows radiodense bilateral nodes and US nodal enlargement and loss of central hilum.

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Fig. 30: Female 33 years old with bilateral breast prosthesis and replacement of the left in 2008. Before long, she has left axillary nodule. Mammogram and US revealed hyperdense and hyperechoic nodes, typical of silicone.

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Fig. 31: 39 year-old man who has a painful right inguinal nodule. US shows enlarged nodes with reactive characteristics. (In hindsight, it was discovered chancre on the penis).

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Fig. 32: Left inguinal mass in a 33 year-old HIV-positive guinean man. US shows bulky node in the thigh that extends through the inguinal canal to pelvis and retroperitoneum. Hypoechoic nodules are seen in the liver and, especially, in the spleen.

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Fig. 33: CT of the same patient: Left paraaortic and iliac bulky nodes are seen. Note the narrowing of the ipsilateral external iliac artery. Hypoattenuating nodules in the liver and spleen. Biopsy findings confirmed large cell lymphoma.

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Fig. 34: 68 year-old man with infiltrating epidermoid carcinoma of the penis. CT scan shows asymmetric and hyperattenuating left inguinal node. Lymphadenectomy is performed, confirming their infiltration.

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Conclusion Many different entities may affect superficial nodes. The main teaching point of the exhibit is to learn to recognize imaging criteria which may help in distinguishing benign from malignant nodes. Thus, the most important parameters are the size, morphology and internal architecture. US for its accessibility and affordability interventionist (fine-needle aspiration or core needle biopsy) allows rapid diagnostic orientation. CT is essential in the staging of neoplasms, as well as providing other nodal features, like the Doppler, crucial to assess a benign or malignant node.

Personal Information José Manuel García Gómez, Rosa Lorente Ramos, Javier Azpeitia Armán, Miguel Grande Bárez, Araceli Muñoz Hernández, Patricia Díez Martínez.

Unidad Central de Radiodiagnóstico de la CAM Hospital Infanta Leonor Madrid (Spain)

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