ultrastructurally the proliferating cells showed a combination of fibroblastic and histiocytic features , with abundant rough endoplasmic reticulum and active production of collagen in many of the cells and long , dendritic cytoplasmic projections with large cytoplasmic vacuoles containing remnants of phagocytosed cellular debris in others .
C0230779
rough endoplasmic reticulum
C0010834
cytoplasmic