Mixed mullerian tumor
Synonyms and keywords: Mixed Mullerian tumor; MMMT; Malignant mixed Mullerian tumor; Carcinosarcoma of the uterus; Sarcomatoid carcinoma of the uterus; Malignant mesodermal mixed tumor; Metaplastic carcinoma

# Overview
Malignant mixed mullerian tumor (MMMT) is a rare uterine sarcoma or carcinosarcoma. Mixed Mullerian tumors are normally composed of both carcinomatous (epithelial) and sarcomatous (mesodermal) components. Mixed Mullerian tumor may be classified according to pathology findings into 2 types: epitheloid subtype and sarcomatoid subtype. Mixed Mullerian tumor may also be classified according to anatomical location into 7 types:  uterine corpus, cervix, ovaries, fallopian tubes, vagina, peritoneum, and extragenital sites. Common risk factors in the development of mixed Mullerian tumor are exposure to radiation, excessive estrogen exposure, obesity, and nulliparity. Mixed Mullerian tumor is more commonly observed among postmenopausal women  between 50 and 60 years old. Early clinical features include postmenopausal vaginal bleeding, pelvic pain, and vaginal discharge. Mixed Mullerian tumors are rare, and they only account for 3 to 4% of all uterine malignancies. The estimated prevalence of mixed Mullerian tumor is 3 cases per 100,000 women in the United States. The diagnosis of mixed Mullerian tumor is made with biopsy. Biopsy findings of mixed Mullerian tumor, include: tumor with carcinomatous and sarcoma-like elements and angiolymphatic invasion. Surgery is the mainstay of therapy for mixed Mullerian tumor. Total hysterectomy in conjunction with surgical staging is the most common approach to the treatment of mixed Mullerian tumor. Prognosis is generally poor, and the 5-year survival rate of patients with mixed Mullerian tumor is approximately 33% to 39%.

# Historical Perspective
- Mixed Mullerian tumor was first described by Ferriera and colleagues in 1951.

# Classification
- Mixed Mullerian tumors are normally composed of both carcinomatous (epithelial) and sarcomatous (mesodermal) components.
- Mixed Mullerian tumor may be classified according to pathology findings into 2 types:
Epitheloid subtype
- Endometroid adenocarcinoma (most common)
- Clear cell carcinoma
- Mucinous carcinoma
- Papillary-serous carcinoma
Sarcomatoid subtype
- Undifferentiated sarcoma
- Rhabdomyosarcoma
- Mixed Mullerian tumor may also be classified according to anatomical location into 7 types:
- Uterine corpus
- Cervix
- Ovaries
- Fallopian tubes
- Vagina
- Peritoneum
- Extragenital sites

# Pathophysiology
- The pathogenesis of mixed Mullerian tumor is characterized by epithelial and stromal growth, and the transdifferentiation of uterine carcinoma into sarcoma.
- The PIK3CA gene has been associated with the development of mixed Mullerian tumor, involving the PI3K pathway.
- Genes involved in the pathogenesis of mixed Mullerian tumor, include: 
- PIK3CA (50% of the tumors)
- PTEN (30% of the tumors)
- PIK3R1 (30% of the tumors)
- On gross pathology, a large cervical mass is a characteristic finding of mixed Mullerian tumor.
- On microscopic histopathological analysis, high-grade stromal sarcoma, poorly differentiated epithelial cells, and angiolymphatic invasion are characteristic findings of mixed Mullerian tumor.

# Causes
- The most important cause of mixed Mullerian tumors is the mutation in genes PTEN, ARID1A, PIK3R1, and POLE.
- Mixed Mullerian tumor may also be caused by chronic estrogen stimulation.

# Differentiating Mixed Mullerian tumor from other Diseases
- Mixed Mullerian tumor must be differentiated from other diseases that cause abnormal vaginal bleeding, abdominal pain, and uterus enlargement such as:
- Uterine leiomyosarcoma
- Adenocarcinoma of the uterus
- Endometrial cancer

# Epidemiology and Demographics
- Mixed Mullerian tumor is rare, it only accounts for 3 to 4% of all uterine malignancies.
- The estimated prevalence of mixed Mullerian tumor is 3 cases per 100,000 women  in the United States.

## Age
- The median age at diagnosis of Mixed Mullerian tumor is 66 years
- Mixed Mullerian tumor is more commonly observed among patients aged between 50 and 60 years old.
- Mixed Mullerian tumor is more commonly observed among postmenopausal women

## Race
- There is no racial predilection for mixed Mullerian tumor.

# Risk Factors
- Common risk factors in the development of mixed Mullerian tumor are exposure to radiation, excessive estrogen exposure, obesity, and nulliparity.

# Natural History, Complications and Prognosis
- Early clinical features include postmenopausal vaginal bleeding, pelvic pain, and vaginal discharge.
- If left untreated, the majority of patients with mixed Mullerian tumor may progress quickly to develop lymph node invasion, metastasis, and death.
- Prognosis is generally poor, and the 5-year survival rate of patients with Mixed Mullerian tumor is approximately 33% to 39%.
- Findings associated with good prognosis include p16 and Mcl-1 gene expression.

# Diagnosis

## Diagnostic Criteria
- The diagnosis of mixed Mullerian tumor is made with biopsy.
- Biopsy findings of mixed Mullerian tumor, include:
- Tumor with carcinomatous and sarcoma-like elements
- Angiolymphatic invasion

## Symptoms
- Mixed Mullerian tumor may be initially asymptomatic.
- Symptoms of mixed Mullerian tumor may include the following:
- Early symptoms
- Abnormal vaginal bleeding, abnormal menstrual periods
- Metrorrhagia in premenopausal women
- Postmenopausal vaginal bleeding 
- Postcoital bleeding
- Advanced symptoms
- Polyuria and dysuria, If a tumor places pressure on the bladder or urethra
- Pelvic pain and dyspareunia
- Fatigue and unexplained weight loss

## Physical Examination
- Patients with mixed Mullerian tumor may have a normal appearance.
- Pelvic examination may be remarkable for:
- Vaginal bleeding
- Enlarged uterus (advanced stage)

## Laboratory Findings
- Laboratory findings associated with mixed Mullerian tumor, may include:
- Anemia
- Elevated CA-125

## Imaging Findings
- Enhanced CT scan and MRI is the imaging modalities of choice for mixed Mullerian tumor.
- On MRI,  findings of mixed Mullerian tumor, may include:
- T1: predominantly isointense to both myometrium (75%) and endometrium (70%)
- T2: hyper-intense to myometrium (90%) either hypo-intense (55%) or isointense (41%) to endometrium.
- On enhanced CT, findings of mixed Mullerian tumor, may include:
- Heterogeneously hypodense and ill defined mass
- Dilatation of uterine cavity

## Other Diagnostic Studies
- Mixed Mullerian tumor may also be diagnosed using laparoscopy, and FDG PET/CT.

# Treatment

## Medical Therapy
- There is no treatment for mixed Mullerian tumor; the mainstay of therapy is supportive care.
- The medical management for mixed Mullerian tumor, include:
- Chemotherapy ifosfamide-based regimen
- Radiotherapy (vaginal brachytherapy)
- Chemotherapy plus radiation therapy

## Surgery
- Surgery is the mainstay of therapy for mixed Mullerian tumor.
- Total hysterectomy in conjunction with surgical staging is the most common approach to the treatment of mixed Mullerian tumor.
- Different surgical procedures for the treatment of  mixed Mullerian tumor, include:
- Total hysterectomy
- Bilateral salpingo-oophorectomy
- Pelvic and para-aortic lymph node dissection
- Cytology of peritoneal washings
- Omentectomy
- Biopsies of peritoneal surfaces

## Prevention
- There are no primary preventive measures available for mixed Mullerian tumor.
- Once diagnosed and successfully treated, patients with mixed Mullerian tumor are followed-up every 6 or 12 months.
- Follow-up testing include pelvic examination, ultrasound, and biomarker monitorization.