Myoglomus Tumor: Glomus Tumor with Prominent Smooth Muscle Differentiation

Glomus tumors are rare benign mesenchymal tumors with various subclassifications. This is a case of a 71-yearold female with a 1.0 cm painful, firm nodule on her right heel who underwent surgical resection. The tumor demonstrated glomus cells with prominent smooth muscle differentiation that stained positively for SMA and caldesmin. Though glomangiomyomas are defined as having both a smooth muscle and vascular component, they do not account for such extensive smooth muscle differentiation. This case report proposes a new entity to better define these such tumors as a myoglomus tumor.