Dermoid Cyst of the Round Ligament in a 3-Year-Old-Girl.

Dermoid cysts result from the anomalous inclusion of ectoderm during the closure of embryologic fusion lines. They can occur in any part of the human anatomy, although they usually arise in the cervicofacial area. Atypical locations, such as the oral cavity or the spermatic cord, have been previously described. Dermoid cysts of the round ligament are exceptional. We present the case of a 3-year-old Caucasian girl, with no previous medical history, with a right inguinal tumor of several months of evolution. Physical examination revealed the presence of a visible soft, relatively fixed, nonpainful mass in the middle third of the inguinal canal (Figure 1; Above, left). With suspected ovarian incarceration in a persistent peritoneal-vaginal duct (PPVD), an ultrasound study was requested, showing a circumscribed oval image in the deep subcutaneous plane, measuring 2.1 × 1.4 × 0.7 cm. It had a capsule and heterogeneous hypoechoic content, with posterior reinforcement. The Doppler study did not show vascularization (Figure 1; Above, right). An inguinotomy was performed, confirming the absence of a PPVD and identifying a solid tumor of approximately 2 × 1.5 cm dependent on the right round ligament (Figure 1; Bottom, left). The round ligament was sectioned caudally with a safety margin and proximally ligated and excised at the level of the internal ring, removing the lesion en bloc together with the ligament. 1175427 PDPXXX10.1177/10935266231175427Pediatric and Developmental PathologyArredondo Montero et al. letter2023