Extended Thymectomy via Thoracoscopy and Cervical Incision in a Child with Anterior Mediastinal Mixed Germ Cell Tumor...

Anterior mediastinal germ cell tumors are uncommon in children, and mixed germ cell tumors containing malignant components are particularly rare. These tumors may occasionally present with endocrine manifestations such as gonadotropin-independent precocious puberty caused by ectopic human chorionic gonadotropin (hCG) secretion. Complete resection is the mainstay of treatment, and extended thymectomy is recommended when the tumor involves or is inseparable from the thymus. Minimally invasive techniques such as video-assisted thoracoscopic surgery (VATS) have been increasingly applied, and in some adult cases, a cervical incision has been combined to ensure removal of the cranial thymic extension. However, pediatric reports of VATS combined with a cervical incision for extended thymectomy are lacking.

We report a 9-year-old boy who presented with gonadotropin-independent precocious puberty characterized by suppressed gonadotropins, elevated serum testosterone, and increased hCG and alpha-fetoprotein levels. Imaging demonstrated a 45 × 25-mm anterior mediastinal mass with features suggestive of teratoma and suspicious cranial solid components. The tumor displaced the thymus cranially into the lower cervical region, prompting the decision for extended thymectomy via a combined thoracoscopic and cervical approach. A small transverse cervical incision was used to mobilize the cranial thymus, and thoracoscopic dissection allowed safe control of thymic veins and arteries and complete en bloc resection of the thymus and tumor. The specimen measured 6 × 5 × 3 cm and weighed 53 g. Histopathology revealed a mixed germ cell tumor composed of mature teratoma and seminoma. The postoperative course was uneventful, tumor markers normalized, and the patient subsequently received adjuvant cisplatin-based chemotherapy. He remains disease-free at follow-up.

To our knowledge, this case represents the 1st pediatric anterior mediastinal mixed germ cell tumor treated with thoracoscopic extended thymectomy combined with a cervical incision. The approach allowed safe and complete resection despite cranial displacement of the thymus, while avoiding sternotomy. Recognition of endocrine manifestations such as hCG-induced precocious puberty is essential for early diagnosis. This case demonstrates that minimally invasive extended thymectomy with cervical extension is feasible in children and may be applied to achieve radical resection of complex anterior mediastinal tumors.