Leiomyosarcoma

Epidemiology:

• 40-60y peak incidence
• 1 in 800 smooth muscle tumours of the uterus

Common sites:

Gross features:

• 6-9cm (avg)
• soft or fleshy
• poorly defined margins
• gray-yellow or pink cut surface
• areas of necrosis or hemorrhage
• 2 patterns:
• bulky, fleshy mass invading the uterine wall
• polypoid mass projecting into the uterine lumen

Histologic features:

• coagulative tumour cell necrosis (if present, tumour is at least of unkown malignant potential)
• abrupt transition between necrotic cells and preserved cells
• ghost cells with cellular details preserved
• little or no inflammatory reaction
• characteristically, blood vessels cuffed by viable cells surrounded by a sea of necrotic tumour
• high mitotic index (>5-10 per 10 HPF depending on presence or absence of other features)
• usually >15 per 10 HPF
• nuclear atypia (less important)
• infiltrative pattern (usually)
• young or pregnant women or exogenous hormones:
• may tolerate these features to a greater degree

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• often recur
• >50% eventually metastasize to distant organs (lung, bone, brain)
• 40% 5-year survival (ranges depending on grade)
• not thought to arise from leiomyoma