Background: Adnexal torsion is an uncommon cause of abdominal pain, and its clinical presentation in children is nonspecific. In some studies, serum D-dimer showed promise as a biochemical marker. The aim of this multicenter prospective observational study was to evaluate the sensitivity and specificity of preoperative serum D-dimer levels for diagnosing adnexal torsion in children and adolescents. Methods: Female patients aged <18 years presenting to the emergency departments of participating centers with symptoms suggestive of adnexal torsion between January 2022 and December 2024 were invited to participate in the study. Preoperative serum D-dimer levels were measured in all patients undergoing surgical exploration. Patients’ characteristics were examined using descriptive and inferential statistics, and the accuracy of preoperative serum D-dimer levels for diagnosing adnexal torsion was assessed using univariate logistic regression and a receiver operating characteristic curve. Results: Twenty-eight patients aged 4–17 years were enrolled. Adnexal torsion was found in 17 patients, on the left side in 4 (23.53%) and on the right side in 13 (76.47%). Almost all patients were treated laparoscopically, and no postoperative complications occurred. Preoperative serum D-dimer levels were higher among patients with adnexal torsion than among those without. The univariate model of serum D-dimer levels had an odds ratio of 1, a sensitivity of 0.77, and a specificity of 0.82 (p = 0.27). Conclusions: No direct association was observed between preoperative serum D-dimer levels and adnexal torsion. Nonetheless, the sensitivity and specificity suggest the possible utility of including serum D-dimer levels in multi-marker diagnostic models to complement rather than replace existing tools.

: Introduction and importance: Rhabdomyosarcoma is the most common pediatric soft tissue sarcoma. It constitutes 4 – 6% of all malignancies in childhood. The botryoid variant is a type of ERMS that is the most common malignancy in the pediatric female genitourinary tract. ERMS of the vagina usually occurs in early childhood, whereas ERMS of the uterus occurs later in age. Since 1959, only 7 cases of uterine botryoid ERMS during infancy have been reported. Case presentation: A 15-months-old girl was admitted to our ED for three reddish, smooth, glistening, polypoidal masses protruding from her vaginal introitus for 9 days. The lesions had a suspicious “grape-like” appearance and tended to come in and out through the vaginal ostium. A pelvic US examination on the patient showed an inhomogeneous aspect of the uterus, which appeared to be occupied and stretched out by an iso-hypoechogenic solid tissue. Additionally, there were some hyperechogenic spots inside as well as evidence of vascular signals on color doppler. A surgical biopsy revealed a malignant mesenchymal tumor consistent with the diagnosis of embryonal rhabdomyosarcoma (ERMS), botryoid variant. Clinical Discussion: The patient completed her first cycle of chemotherapy with ifosfamide, vincristine, and dactinomycin (IVA). When she was 18 months old, she underwent a hysterectomy, which removed the entire mass with a Pfannenstiel approach. The postoperative course presented with no complications. Follow-up visits were scheduled quarterly. Conclusion: Botryoid ERMS of the uterus is a diagnosis not to be missed in an infant. Since rapid diagnosis and treatment are necessary, clinicians should be aware of its presentation to assure optimal management. Highlights: