Approach to intensely enhancing neck nodes

Abstract

E nlarged cervical lymph node is one of the most common causes of a mass lesion in the neck. Although ultrasonography can be used as an initial investigative tool to assess neck nodes, computed tomography (CT) and magnetic resonance imaging (MRI) have an advantage in assessing disease extent and evaluating any primary head and neck pathology. MRI has a very high contrast sensitivity compared with CT and hence most lymph nodal diseases show postcontrast enhancement, making it difficult to appreciate differential nodal enhancement. In addition, absence of direct measurement of signal intensity makes interpretation subjective. In contrast, CT scan can differentiate varying degrees of enhancement based on Hounsfield unit (HU) values rendering higher objectivity. To reduce radiation exposure, a contrast-enhanced CT scan is performed directly in most cases. In pediatric patients, however, Doppler ultrasonography and MRI may take preference as investigative tools.Almost all conditions affecting cervical nodes cause postcontrast enhancement. Of these, only few conditions cause intense enhancement in cervical nodes. We define intense contrast enhancement as above 120 HU (Fig. 1). The sternomastoid muscle shows a CT value of 60-80 HU on postcontrast scan for comparison. In this pictorial essay, we discuss the various causes of intensely enhancing solid neck nodes and important features that may help differentiate these conditions. The images given below were obtained on two CT machines: Siemens Somatom Definition AS (128 slice, 120 Kv, 250 mAs, slice thickness 1 mm, scan interval 0.8 mm, pitch 0.8) and Spiral CT systems CT/I GE Medical systems (single slice spiral CT, slice thickness 5 mm, no overlap).Common causes of intensely enhancing neck nodes are as follows: metastases from hypervascular primaries, most commonly papillary thyroid carcinoma; Castleman disease; Kikuchi disease; Kimura disease; and rarely, angioimmunoblastic lymphadenopathy (1). Metastatic neck nodes from hypervascular primary malignancyMetastatic neck nodes from hypervascular primaries show intense enhancement due to increased vascularity. The primary hypervascular malignancies that metastasize to neck nodes include papillary and medullary carcinoma of thyroid, renal cell carcinoma, Kaposi sarcoma, and neuroendocrine tumors. Most common cause of hypervascular metastases from a head and neck primary is the papillary thyroid cancer. 1) Thyroid cancer: Papillary thyroid cancer has a high propensity to metastasize to nodes (30%-90%); other thyroid cancers with frequent node metastasis are medullary carcinoma (50%) and anaplastic carcinoma (40%) (Figs. 2, 3) (2). Besides intense enhancement, nodal calcification (50%-69%) and cystic change (20%) may also be noted. In larger tumors, CT scan may show a thyroid mass invading adjacent structures (trachea, esophagus). A heterogeneous thy- Here, we present a pictorial review of intensely enhancing neck nodes. While enhancement in a cervical node is a common radiologic finding on contrast-enhanced computed tomogra...

Role of computed tomography scan in diagnosis of retroperitoneal masses

“…Contrast enhancement is variable within lymph nodes and when present, homogenous, heterogenous or rim enhancement have all been described. 20 CT scanners are incapable of demonstrating intranodal architecture, lymph nodes that are normal in size but infiltrated with neoplastic cells cannot be distinguished as abnormal by CT. Furthermore, CT usually cannot differentiate between benign and malignant causes of lymph node enlargement.…”

Imaging of metastatic cervical nodes: is CT helpful in differentiation of squamous cell carcinoma (SCC) from non-SCC groups?

“…Besides intense enhancement, intra-nodal calcifications, either coarse or punctate (in 50-69%), and cystic changes (20%) may be noted. In larger tumors, a CT scan may show a thyroid mass invading adjacent structures (trachea, esophagus) [16][17][18][19][20].…”