On the Neurogenesis of So-Called Granular Cell Myoblastoma

Abstract

Study of 52 tumors originally diagnosed granular cell myoblastoma revealed a histogenetic relationship to peripheral nerves. Large granular cells were often found within the perineurium of nerve twigs well beyond the reaches of the tumors proper, appearing to have developed there rather than having invaded the nerves. At the margins of many of the tumors, coarse extensions ramified through contiguous tissue for varying distances, nearly always centering around a bundle of axis cylinders and having a border resembling nerve sheath. Such structures extended into the solid portion of the tumors. Four tumors illustrated gradations between the conventional type of neurofibroma and granular cell tumors. 15 tumors embedded in striated muscle produced, in it, misleading degenerative changes. Myofibrillae had become fragmented to form fine granules which, however, looked decidely different from those of the tumor cells when impregnated by the Bodian technic. No tumors exhibited malignant change. The term granular cell neurofibroma is proposed for the tumors heretofore called "granular cell myoblastoma.".