Ultrastructural study of urinary bladder leiomyosarcoma

Three cases of spindle cell neoplasms of the urinary bladder were subjected to EM study. They showed haphazard arrangement of myofilaments, abundant rough endoplasmic reticulum and free ribosomes. Irregular nuclear borders and frequent nuclear clefts with irregularly clumped chromatin were also evident. Infrequent pinocytic vesicles were also seen. These features differentiate clearly between these types of tumors on one hand and sarcomatoid carcinoma, spindle cell fibrotic nodules and inflammatory pseudotumor on the other hand