Superior Vena Cava Leiomyosarcoma

**Semantic type:** Neoplastic Process

**Definition:** An aggressive malignant smooth muscle neoplasm, arising from the superior vena cava. It is characterized by a proliferation of neoplastic spindle cells.

**Synonyms:** - Leiomyosarcoma of Superior Vena Cava - Leiomyosarcoma of the Superior Vena Cava