Cancerous tumours of the uterus

A cancerous tumour of the uterus can invade, or grow into, and destroy nearby tissue. It can also spread, or metastasize, to other parts of the body. Cancerous tumours are also called malignant tumours.

Endometrial carcinomas begin in the lining of the uterus (called the endometrium). More than 95% of all uterine cancers are endometrial carcinoma.

Endometrioid carcinoma makes up 75%–80% of all endometrial carcinomas. Endometrioid carcinomas form in the glands in the endometrium.

There are different types, or variants, of endometrioid carcinoma. One variant is endometrioid carcinoma with squamous differentiation. When these tumours are made up of cancerous gland cells and non-cancerous squamous cells, they are called adenocanthomas. When they are made up of cancerous gland cells and squamous cells, they are called adenosquamous, or mixed cell, carcinoma.

Other variants of endometrioid carcinoma include:

• villoglandular
• secretory
• ciliated cell

The following types of endometrial carcinoma can also develop:

• mucinous adenocarcinoma
• serous adenocarcinoma (papillary serous carcinoma)
• clear cell adenocarcinoma
• squamous cell carcinoma
• transitional cell carcinoma
• small cell carcinoma
• undifferentiated carcinoma

Carcinosarcoma is also called malignant mixed mesodermal tumour or malignant mixed mullerian tumour (MMMT). It is another type of cancer that starts in the endometrium. It has features of both carcinomas and sarcomas.

In the past, carcinosarcomas were grouped with uterine sarcomas. Doctors now consider them a type of poorly differentiated endometrial carcinoma.

Uterine sarcomas begin in the muscle or connective tissue of the uterus. About 2%–5% of all uterine cancers are uterine sarcoma.

Uterine leiomyosarcoma develops in the muscle layer of the uterus wall (called the myometrium). It is the most common type of uterine sarcoma.

Endometrial stromal sarcoma is a rare type of uterine sarcoma. It develops in the supporting connective tissue of the endometrium. Low-grade stromal sarcomas most often occur in premenopausal women. High-grade stromal sarcomas most often occur after menopause.

Undifferentiated sarcomas are a rare, aggressive type of endometrial stromal sarcoma.

Gestational trophoblastic disease (GTD) includes several rare tumours that start in the tissues that would normally develop into the placenta following conception (the joining of sperm and egg). They can occur in pregnant or recently pregnant women.

Find out more about gestational trophoblastic disease, including hydatidiform mole and gestational choriocarcinoma.