It is as a rare
soft tissue sarcoma showing two or more distinct types of malignant
It is generally
thought that malignant mesenchymomas are high grade sarcomas
with a poor prognosis. However, low grade malignant mesenchymomas have
been reported which had a better prognosis.
It is essential
to study all areas of the tumour by means of immuno-histochemistry
for an accurate histological diagnosis of malignant mesenchymoma.
Age: Mainly adults.
These tumours are frequently located in the
trunk (for example, the chest wall and retroperitoneum)and
lower extremities (usually on the thigh).
Consists of 3 most
common components: 1.Liposarcoma
components in malignant mesenchymoma are not dedifferentiated
and other distinct mesenchymal components such as regions of
liposarcoma , chondrosarcoma, and osteosarcoma are neoplastic,
regardless of their histological grades.
tumours with two or more phenotypes-
i) Malignant Triton tumours ; ii)liposarcoma with smooth
muscle, cartilaginous, or osseous differentiation; iii)
dedifferentiated liposarcoma and iv) dedifferentiated chondrosarcoma.
Soft tissue tumours of uncertain differentiation