Presentation
Dyspnoea
Patient Data
Large lobulated mass in the anterior mediastinum.
Mediastinal soft tissue density mass lesion. The lesion does not enhance and has a hypodense core. The adjacent lungs demonstrate some compressive atelectasis.
Case Discussion
Surgical removal of the mediastinal mass and four regional lymph nodes and pleural nodule.
Histology
MICROSCOPIC FEATURES:
Mediastinal mass: Sections show a non-seminomatous mixed germ cell tumour showing extensive tumour necrosis. The percentage of viable tumour tissue is estimated to be approximately 20%. 100% of the viable tumour is a yolk sac tumour showing a variety of patterns including some cystic areas with hyaline globules in cells lining a cyst. Schiller-Duval bodies are readily identified. The left-sided soft grey nodule is a keratin-filled cyst surrounded by entirely necrotic tissue consistent with entirely necrotic teratoma. No immature teratoma component is identified. A few foci showing larger more pleomorphic cells are present which are the pleomorphic cell type pattern of yolk sac tumour (alpha-fetoprotein positive, CD30 and beta-HCG negative). There is no evidence of embryonal carcinoma, seminoma or choriocarcinoma on routine or immunohistochemistry stains. Alpha-fetoprotein stain shows only a few foci of positivity within the yolk sac tumour.
Pleural nodule: Sections show both viable and necrotic yolk sac tumour with a small amount of attached diathermied skeletal muscle. Focally viable yolk sac tumour abuts an inked margin immediately adjacent to an area of diathermied margin, over a distance of approximately 5 mm
Lymph nodes: no viable tumour
FINAL DIAGNOSIS:
- Mediastinal tumour - non-seminomatous mixed germ cell tumour.
- Approximately 20% of tumour tissue viable.
- 100% of the viable tumour is yolk sac tumour. Entirely necrotic teratoma also present. No immature teratoma identified.