A rare case of brain metastatic of primary mediastinal yolk sac tumor

Abstract

Primary yolk sac tumors are extragonadal germ cell tumors commonly seen in children and young adults. They are more common in men. Germ cells tumor on histopathological characteristics is classified as seminoma and non-seminomatous (NSGC). The rarest form of NSGC is an extragonadal yolk sac tumor of mediastinum. Clinical presentations are not specific and may imitate other chronic disease such as other malignancies or tuberculosis such as chest discomfort, vena cava superior syndrome, fever, weight loss, and chronic cough. Immunohistochemistry showed a positive result in Alpha-fetoprotein and pan-cytokeratin. Due to its rarity, brain metastases' clinical signs and symptoms, anatomical sites, and characteristics are less well documented. However, the metastatic brain process gave similar histological findings to the primary site. Additional radiological and laboratory tests can be carried out to identify other metastatic processes. Standardized treatment of primary mediastinal sac tumors with brain metastasis has not yet been established. Combining chemotherapy, surgery and radiation treatment could improve overall outcomes and prognosis. We present a scarce case of primary mediastinal yolk sac tumor with metastatic brain process in a 32-year-old male with a short survival period.

Keywords: Brain metastases; Extragonadal tumor; Non-seminomatous germ cell tumor; Yolk sac tumor.

Fig. 1

The thorax CT scan obtained on the first admission showed a solid mass in the middle anterior mediastinum with the size of 7.65 × 8.28 × 11.3 cm.

Fig. 2

Brain CT scan before (a) and after (b) intracerebral hemorrhage evacuation from the 7 months after initial treatment. Intracerebral hemorrhage volume was ±27 cc with midline shift <0.5 cm; after surgery, there was a hypodense area which indicates peritumoral edema. (c) Brain MRI with contrast before evacuation showed intratumoral hemorrhage.

Fig. 3

Histological specimen from the brain tissue (a) H&E stain 200x insert and (b) H&E stain 400x insert. Both specimens showed the proliferation of anaplastic cells with prominent nuclei, hyperchromatic, which is characteristic of the metastatic cell. These cells form epithelial glands, with intervening vessels forming schiller Duval bodies (shown in red arrow). Further, we performed immunohistochemistry, and the result was positive for PanCK and AFP, consistent with an endodermal sinus tumor.