Case 203 - Discussion

Uploaded: 2008-04-05, Updated: 2008-04-05

 

MICROSCOPIC DESCRIPTION:
The tumor displays extensive necrosis and focal myxoid degeneration. In the non-necrotic areas, the tumor is composed of fascicles of highly pleomorphic round, oval or spindle neoplastic cells with abundant pale or bright eosinophilic cytoplasm. The nuclei of the tumor cells are hyperchromic with coarse chromatin and occasionally prominent nucleoli. Scattered giant neoplastic cells are noted. Frequent mitotic figures are identified (up to 34/10HFP). All these microscopic features support a diagnosis of leiomyosarcoma of the uterus.

 

ELECTRON MICROSCOPY:
Ultrastructurally, the tumor consists of pleomorphic oval or spindle neoplastic cells in a myxoid background. The cytoplasm is intermediate to abundant with many ribosomes, swollen mitochondria and dilated cisternae of rough and smooth endoplasmic reticulum. Frequent primary and secondary lysosomes are noted. Specifically, frequent bundles of myofilaments and occasional dense bodies are present in the cytoplasm. The nuclei of the tumor cells are round, oval or spindle with high pleomorphism and condensed chromatin and occasional prominent nucleoli.

 

 

Leiomyosarcoma of the Uterus

This uterine neoplasm is grossly large (maximum dimension 10.0cm) and well-demarcated with a heterogeneously brown, pink, tan and yellow cut surface with focal necrotic areas. Microscopically, This tumor displays extensive necrosis and focal myxoid degeneration. In the non-necrotic areas, the tumor is composed of fascicles of highly pleomorphic round, oval or spindle neoplastic cells with abundant pale or bright eosinophilic cytoplasm. The nuclei of the tumor cells are hyperchromic with coarse chromatin and occasionally prominent nucleoli. Scattered giant neoplastic cells are noted. Frequent mitotic figures are identified (up to 34/10HFP). All these microscopic features support a diagnosis of leiomyosarcoma of the uterus.

Leiomyosarcoma accounts for approximately 1.0% of all uterine malignant tumors and it is the most common pure uterine sarcoma. Uterine leiomyosarcoma has no association with leiomyoma. Grossly, it is typically solitary with an average diameter of 8.0 cm. It is usually poorly demarcated and fleshy with frequent hemorrhage and necrosis. Histologically, the major diagnostic criteria of uterine leiomyosarcoma include: 1. coagulative necrosis of tumor cells; or 2. diffuse, moderate to severe cytological atypia and a mitotic count no less than 10/10 high-power field. The tumor necrosis must be distinguished from degenerative changes in uterine leiomyomas, especially those with large size. The areas of tumor necrosis are typically sharply demarcated from the viable tumor tissue with preserved cell contour and no marked inflammatory reaction.

REFERENCES

Fattaneh A. Tavassoli, Peter Devilee. World Health Organization: Tumors of the Breast and Female Genital Organs.  October, 2003: page 236-238.