From the Guidelines
A hypoechoic lymph node is a concerning finding that warrants further evaluation, as it can indicate pathological changes, and management typically involves a comprehensive assessment including patient history, physical examination, and possibly additional imaging or biopsy depending on clinical context, as recommended by recent guidelines 1. When a hypoechoic lymph node is identified, clinical correlation with other features such as size (nodes >1 cm are concerning), shape (round rather than oval), loss of fatty hilum, irregular borders, and increased vascularity is important.
- Hypoechoic lymph nodes may be associated with various conditions including infection, inflammation, or malignancy.
- The hypoechoic appearance occurs because the normal fatty hilum is replaced by more cellular tissue that absorbs rather than reflects ultrasound waves.
- While hypoechoic nodes can be concerning, they are not always malignant, as reactive lymph nodes from infection can also appear hypoechoic.
- Fine needle aspiration or core needle biopsy may be necessary if malignancy is suspected, as supported by studies such as 1 and 1.
- Regular follow-up imaging may be recommended for nodes with borderline features to monitor for changes over time, as suggested by 1. The most recent and highest quality study 1 provides guidance on the management of hypoechoic lymph nodes, emphasizing the importance of a comprehensive assessment and consideration of additional imaging or biopsy.
From the Research
Hypoechoic Lymph Node Characteristics
- A hypoechoic lymph node can be characterized by its round or ovoid shape, discrete hypoechoic nodules, or multiple confluent lobulated heterogeneous or homogeneous hypoechoic masses 2
- The sonography of lymph nodes can also demonstrate venous invasion by a malignant lymph node as a loss of echogenicity in the vessel wall 2
- Hypoechoic areas in a lymph node can represent necrosis or metastatic hemorrhages, but also suppuration in inflamed lymph nodes 3
Diagnosis and Evaluation
- Ultrasonography is a valuable tool to evaluate cervical lymphadenopathy and to clarify the histopathological features of the affected lymph nodes with the aid of aspiration cytology 2
- Endoscopic ultrasound-guided fine-needle aspiration is an important adjunct for accurate lymph node assessment for malignancy 4
- Several parameters can be evaluated using ultrasound, including lymph node size, margins, echogenicity, echopattern, acoustic transmission, presence and distribution of vascular flow, and vascular flow indices 5
Differential Diagnosis
- Lymph nodes in lymphomas may be indistinguishable from reactive lymph nodes, even when using Doppler option, as well as morphologically difficult to distinguish from metastases 3
- Metastatic lymph nodes can mimic other conditions, such as nodular, separated postoperative thyroid fragments, a lateral neck cyst, chemodectoma, or neuroma 3
- The appearance of lymph nodes in granulomatous diseases, such as tuberculosis or sarcoidosis, can be very similar to that of typical metastatic lymph nodes or lymphomas 3