GRANULAR CELL MYOBLASTOMA OF THE ORBIT

Abstract

WITHIN recent years much has been written by the pathologists about a type of tumor variously designated by the names "myoblastic myoma," "myoblastoma," "rhabdomyoma" and "granular cell myoblastoma." Confusion still exists as to the correct terminology, but all are agreed on the pathologic picture of this tumor type. Using the name myoblastoma (<i>Myoblastenmyom</i>), Abrikossoff,¹in 1926, first described this peculiar tumor of striated muscle tissue. The characteristic microscopic features may be summarized as follows: (1) large polyhedral cells, 20 to 60 microns in diameter, constitute a nodular accumulation of neoplastic cells; (2) the cytoplasm stains only faintly with eosin and contains many coarse neutrophilic granules; (3) cross or longitudinal striations are rarely seen; (4) the nuclei are small and never show the irregularity associated with malignancy; (5) the tumor cells, individually or in groups, are surrounded by a thin network of connective tissue fibers; (6) the cells are