Leiomyoma of the orbit.
A 5-year-old boy had a one-year history of inability to adduct the left eye and redness. Examination showed a medial orbital mass indenting the globe without proptosis. A well-encapsulated mass was removed surgically. On light microscopy it seemed to be a neurofibroma. Transmission electron microscopy showed that the tumor was composed of cells with cigar-shaped nuclei, cytoplasmic and plasmalemmal densities, fine filaments, surface-connected vesicles, and basement membrane. These features were characteristic of leiomyoma.
D001485:Basement Membrane / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D002675:Child, Preschool; D003593:Cytoplasm / Q000648:ultrastructure; D005654:Fundus Oculi; D006801:Humans; D007889:Leiomyoma / Q000175:diagnosis / Q000601:surgery / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D009918:Orbital Neoplasms / Q000175:diagnosis / Q000601:surgery / Q000648:ultrastructure*; D014057:Tomography, X-Ray Computed