Purpose <p>Tunneled central venous catheters (CVC) are essential medical devices for pediatric patients facing extended treatment periods. This study aimed to demonstrate the usefulness of ultrasound in evaluating complications in subcutaneous tissue associated with unplanned extraction of tunneled CVC.</p> Methods <p>Twenty-five patients who underwent ultrasound examination for suspected complications in the subcutaneous tissue associated with tunneled areas from CVC were included. The following patient characteristics and imaging findings were evaluated: infection in subcutaneous tissue, high echogenicity and hypoechoic effusion around the catheter within the subcutaneous tissue, and hyperechoic foci around the catheter. Patients with CVC were classified into two groups: those with and those without unplanned extraction of tunneled CVC. Fisher’s exact test was used to compare the two groups.</p> Results <p>Nine patients had unplanned extraction of tunneled CVC. A significant difference was found in infection at tunneled areas (presence/absence in patients with vs. those without unplanned extraction = 7/2 vs. 2/14, P = 0.002), as well as in hypoechoic effusion around the catheter within the subcutaneous tissues (presence/absence in patients with vs. those without unplanned extraction = 9/0 vs. 3/13, P &lt; 0.001). However, no significant differences were found in the presence or absence of high echogenicity (presence/absence in patients with vs. those without unplanned extraction = 7/2 vs. 6/10, P = 0.097) or hyperechoic foci around the catheter (presence/absence in patients with vs. those without unplanned extraction = 3/6 vs. 1/15, P = 0.116).</p> Conclusion <p>The ultrasound findings were useful for determining the necessity of tunneled CVC extraction. These results will be helpful for improving management of pediatric patients with CVC.</p>