label: Intramuscular Myxoma
label_lc: intramuscular myxoma
description: "A benign, painless soft tissue tumor that arises in a muscle, usually in a large muscle of the thigh, buttocks, shoulder, or upper arm.  It is associated with point mutations of the GNAS gene.  Grossly it is characterized by a gelatinous and lobulated cut surface.  Morphologically it is composed of uniform spindled and stellate-shaped cells without atypia.  The cells are separated by myxoid stroma.  No recurrences have been reported."