Mixed Mullerian tumor

Tumor of the uterus containing a mixture of epithelial and mesenchymal elements.

A malignant mixed Müllerian tumor, is a cancer found in the uterus, the ovaries, the fallopian tubes and other parts of the body that contains both carcinomatous (epithelial tissue) and sarcomatous (connective tissue) components. 

It is divided into two types, homologous and heterologous.

Homologous is the sarcomatous component is made of tissues found in the uterus such as endometrial, fibrous and/or smooth muscle tissues.

The heterologous type is made up of tissues not found in the uterus, such as cartilage, skeletal muscle and/or bone.

20% of patients with tumor clinically confined to the uterus have surgically documented metastases.

A MMT accounts for between two and five percent of all tumors derived from the body of the uterus.

MMTs are found predominantly in postmenopausal women with an average age of 66 years. 

Risk factors include obesity, exogenous estrogen therapies, and nulliparity. 

Other  potential risk factors include tamoxifen therapy and pelvic irradiation.

Stage I and II patients have a recurrence rate of greater than 50%.

The behavior of MMT overall is more related to the type and grade of the epithelium than the sarcoma, which suggests the sarcomal portion is an atypical bystander than primary driver of the tumor. 

When purely endometrial tumors are compared to MMTs, the MMT tumor tends to have a worse prognosis.

Carcinosarcoma of the uterus are fleshier than adenocarcinomas, may be bulky and polypoid, and sometimes protrude through the cervical os. 

The tumors consist of adenocarcinoma (endometrioid, serous or clear cell) mixed with the malignant mesenchymal sarcoma elements; 

Sarcomatous components may also mimic extrauterine tissues Ike striated muscle, cartilage, adipose tissue, and bone.

Metastases usually contain only epithelial components.

Outcome of MMTs is determined primarily by depth of invasion and stage. 

The prognosis is influenced by the grade and type of the adenocarcinoma, being poorest with serous differentiation. 

MMTs are highly malignant; a stage I tumor has an expected five-year survival rate of 50%, while the overall five-year survival rate is less than 20%.

Staging of uterine MMTs:

Stage I. Carcinoma is confined to the corpus uteri itself.

Stage II. Carcinoma involves the corpus and the cervix.

Stage III. Carcinoma extends outside the uterus but not outside the lesser pelvis.

Stage IV. Carcinoma extends outside the true pelvis or involves the mucosa of the bladder or the rectum.

Women with high stage uterine carcinosarcoma (stage 3 or 4) who were treated with combination chemotherapy including Ifosfamide, were at lower risk of disease progression and death than those women treated with Ifosfamide alone. 

Radiotherapy to the abdomen is  not associated with improved survival.

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