Myoblastomas are tumors which may occur anywhere in the body in relation to striated muscle. They are composed of myoblasts, the ancestral cells of striated muscle. Although commonly considered rare, over fifty cases have been described since the first report seven years ago by Abrikossoff.1 Only two of the cases were reported in the English literature, until Klemperer2 recently wrote an article adding six cases, of which the case reported here is one.
These tumors are composed of two types of cells: a polygonal cell with granular cytoplasm (resembling xanthoma cells) and a ribbon-like syncytial mass (resembling early embryonal muscle fiber). Some of these tumors, especially those involving the vocal cords, often show hyperplasia of the overlying epithelium, thus simulating carcinoma, from which they can be differentiated by the scarcity of mitoses or atypical cells. The tumors differ from xanthoma, microscopically, by the absence of fat, as shown by
KLEINFELD L. MYOBLASTOMA OF THE LARYNXREPORT OF A CASE. Arch Otolaryngol. 1934;19(5):551–555. doi:10.1001/archotol.1934.03790050016002