A malignant germ cell neoplasm that is the most common ovarian malignancy in childhood, with ultrasound showing a unilateral, predominantly solid, homogeneous ovarian mass.

• A. Dysgerminoma
• B. Endodermal sinus tumor
• C. Embryonal carcinoma
• D. Choriocarcinoma

Answer: (A)

Dysgerminoma is the ovarian germ cell tumor most commonly seen in children, and its imaging often shows a unilateral, solid, and relatively homogeneous mass. This uniform solid appearance aligns with how dysgerminomas typically present on ultrasound, with the lesion arising from one ovary and appearing well circumscribed and echogenic throughout, sometimes with increased blood flow on Doppler.

Other malignant germ cell tumors have imaging or marker patterns that differ. A yolk sac tumor (endodermal sinus tumor) more often shows heterogeneous echotexture and is commonly associated with elevated AFP. Choriocarcinoma tends to elevate hCG. Embryonal carcinoma is rarer and lacks the characteristic homogeneous solid pattern described here. Thus, the unilateral, predominantly solid, homogeneous ovarian mass in a child best fits dysgerminoma.