other ultrastructural features observed in rhabdomyosarcomas , for which the diagnosis is confirmed by the presence of diagnostic ultrastructural features or by the presence of cross-striations observed by light microscopy , include large irregularly shaped nuclei with projections and invaginations , free ribosomes closely associated with filaments , rough endoplasmic reticulum that is often dilated , glycogen , and external lamina , prominent nucleoli , and pleomorphic mitochondria .
C1179933
free ribosomes
C0230779
rough