Objective: To study the ultrasonographic manifestations and clinical features of common pediatric testicular germ cell tumors (TGCT) in children.
Methods: We retrospectively analyzed the laboratory, ultrasonographic and clinical data on 92 children with TGCT diagnosed in Shanghai Children's Hospital from March 2013 to January 2019, and investigated the values of the serum alpha-fetoprotein (AFP) level and maximum diameter of tumors in the diagnosis of benign and malignant tumors using the ROC curve.
Results: Of the 92 cases of pediatric TGCT, 64 (69.6%) were pathologically confirmed as benign tumors, including 40 cases of teratoma (62.5%), 18 cases of epidermoid cyst (28.1%) and 6 cases of dermoid cyst (9.4%), and the other 28 (30.4%) as malignant neoplasms, including 26 cases of yolk sac tumor (YST, 92.9%) and 2 cases of mixed germ cell tumor (MGCT, 7.1%). Ultrasonography showed that 62.5% of the teratomas were cystic-solid mixed (25/40) and 32.5% solid masses (12/40), that 33.3% of the epidermoid cysts exhibited a typical sign of "onion ring" (6/18) and 22.2% that of capsular calcification (4/18), and that 42.3% of the YSTs displayed isoechoic (11/26), 30.9% hypoechoic (8/26) solid masses without calcium and 26.9% cystic anechoic lesions (7/26). Color Doppler blood flow imaging manifested abundant blood flow signals in most of the YSTs (25/26, 96.2%) but none in either the epidermoid or the dermoid cysts. The area under the ROC curve (AUC) of the serum AFP value was 0.985, with an optimal cutoff value of 124.2 ng/ml, and the sensitivity and specificity of AFP in the diagnosis of benign and malignant tumors were 92.9% and 93.7%, respectively. The AUC of the maximum diameter of the tumors was 0.796, with an optimal cutoff value of 2.7 cm, and the sensitivity and specificity of the maximum diameter of the tumors in the diagnosis of benign and malignant neoplasms were 57.1% and 93.7%, respectively.
Conclusions: Ultrasonographic images have different characteristic manifestations for different pathological types of pediatric TGCT. Pediatric TGCT has a good prognosis and radical orchiectomy should be considered for the treatment of the tumors with serum AFP ≥ 124.2 ng/ml and a diameter ≥ 2.7 cm.
Keywords: alpha-fetoprotein; children; clinical features; testicular germ cell tumor; tumor diameter; ultrasonography.