Comparison of Sonographic Features of Benign and Neoplastic Deep Lymph Nodes in Dogs

Abstract

The differentiation of benign vs. neoplastic lymph nodes impacts patient management. Specific sonographic features are typically considered when assessing lymph nodes in dogs. However, the usefulness of these criteria in distinguishing benign vs. malignant lymph nodes remains largely unknown, especially for deep lymph nodes. Our aim was to compare sonographic features in benign and neoplastic deep lymph nodes with the hope of identifying predictive criteria. Thirty-one deep lymph nodes (16 mesenteric, 10 medial iliac, three hepatic, one sternal, and one cranial mediastinal) in 31 dogs were examined prospectively with B-mode and Color flow Doppler. Lymph nodes were aspirated using ultrasound-guidance and final diagnosis were established based on cytologic and/or histopathologic interpretation. Prevalence of each sonographic feature and combinations of two features was calculated for each group and compared using a χ(2) -test or Student's t-test for unequal variances. Ten lymph nodes were benign (hyperplastic and/or inflammatory) and 21 were neoplastic. All were hypoechoic, except for one neoplastic lymph node. Maximal short-axis diameter (P=0.0006) and long-axis diameter (P=0.01), and SA/LA ratio (P=0.008) were increased significantly for neoplastic (2.8, 5.5 cm, and 0.50, respectively) vs. benign (1.2, 3.8 cm, and 0.34, respectively) lymph nodes. The prevalence of other features was similar between groups. Doppler evaluation was possible in 77% of lymph nodes, but there was no significant difference between groups. When any two ultrasound features were combined, the only difference between benign and neoplastic lymph nodes was for the combination of contour regularity and appearance of the perinodal fat (P=0.03).

Clinical characteristics and outcome in dogs with small cell T‐cell intestinal lymphoma

“…All medical records were reviewed, and data collected included signalment, body weight, body condition score (BCS), owner reported clinical signs at presentation, staging diagnostics (including abdominal ultrasound images which were all reviewed by single board-certified radiologist [ALZ]), treatment, and date of death. Lymph nodes were considered enlarged based on the opinion of ALZ using previously reported size guidelines(19–21). Classification for lymph node enlargement was binary (yes/no).…”

Enhanced Sonographic Imaging to Diagnose Lymph Node Metastasis: Importance of Blood Vessel Volume and Density

“…These changes include release of metalloproteinases that degrade the extracellular matrix, secretion of growth factors to promote neovascularization (34), and development of sinus hyperplasia (35). In the diagnosis of lymph node metastasis by B-scan sonography, the clinical criteria currently used are increases in nodal size and cortical thickness, changes in nodal shape, infiltration of surrounding structures, presence of inhomogeneous internal echo patterns (including necrosis), absence of echorich hilar structures, and extracapsular spread (14,36). However, these changes only become pronounced once the tumor has already grown to some extent.…”

“…The criteria used for diagnosing lymph node metastasis with gray-scale sonography are lymph node size (short-axis diameter/long-axis diameter), cortical thickness, shape, nodal borders, central necrosis, absence of echo-rich hilar structures, and extracapsular spread (13)(14)(15). Among these criteria, nodal size and depiction of necrosis are the most important sonographic criteria (16).…”

Prevalence, location and concurrent diseases of ultrasonographic cyst‐like lesions of abdominal lymph nodes in dogs

“…Many different ultrasonographic features have been studied to differentiate benign from malignant lymph nodes. Malignancy has been significantly associated with an increased number of detectable lymph nodes and a rounded shape (Llabrés-Díaz 2004), with heterogeneity (Llabrés-Díaz 2004, Kinns and Mai 2007), with a maximal short and long axis ratio (De Swarte and others 2011), with a combination of irregular and hyperechoic perinodal fat (De Swarte and others 2011), with an altered vascularisation pattern (Nyman and others 2005, Salwei and others 2005) and with high values of pulsatility and resistivity index (Nyman and others 2005, Prieto and others 2009). …”