malignant glomus tumor (MONDO_0003340) is a very rare morphologic variant of glomus tumor with a size greater than 2 cm. The tumor arises in subfascial or visceral tissues. It is characterized by the presence of atypical mitotic figures, or marked nuclear atypia, or the combination of both. It has an aggressive clinical course. Also known as: glomangiosarcoma, glomus tumor, malignant, malignant glomus neoplasm.