Investigations by the physician include imaging (ultrasound, CAT scan, MRI) and, if possible, obtaining a tissue diagnosis by biopsy, hysteroscopy, or D&C.

Ultimately the diagnosis is established by the histologic examination of the specimen. Typically malignant lesions have >10 mitosis per high power field. In contrast a uterine leiomyoma as a benign lesion would have < 5 mitosis per high power field.

Unusual or postmenopausal bleeding may be a sign of a malignancy including uterine sarcoma and needs to be investigated. Other signs include pelvic pain, pressure, and unusual discharge. A nonpregnant uterus that enlarges quickly is suspicious. However, none of the signs are specific. Specific screening test have not been developed; a Pap smear is a screening test for cervical cancer and not designed to detect uterine sarcoma.

The only reliable way to determine whether a soft-tissue tumour is benign or malignant is through a biopsy. There are two methods for acquisition of tumour tissue for cytopathological analysis;

- Needle Aspiration, via biopsy needle

- surgically, via an incision made into the tumour.

A pathologist examines the tissue under a microscope. If cancer is present, the pathologist can usually determine the type of cancer and its grade. Here, 'grade' refers to a scale used to represent concisely the predicted growth rate of the tumour and its tendency to spread, and this is determined by the degree to which the cancer cells appear abnormal when examined under a microscope. Low-grade sarcomas, although cancerous, are defined as those that are less likely to metastasise. High-grade sarcomas are defined as those more likely to spread to other parts of the body.

For soft-tissue sarcoma there are two histological grading systems : the National Cancer Institute (NCI) system and the French Federation of Cancer Centers Sarcoma Group (FNCLCC) system.

Soft tissue sarcomas commonly originate in the upper body, in the shoulder or upper chest. Some symptoms are uneven posture, pain in the trapezius muscle and cervical inflexibility [difficulty in turning the head].

The most common site to which soft tissue sarcoma spreads is the lungs.

The diagnosis of synovial sarcoma is typically made based on histology and is confirmed by the presence of t(X;18) chromosomal translocation.

Imaging studies such as X-rays, computed tomography scans, or MRI may be required to diagnose clear-cell sarcoma together with a physical exam. Normally a biopsy is also necessary. Furthermore, a chest CT, a bone scan and positron emission tomography (PET) may be part of the tests in order to evaluate areas where metastases occur.

Two cell types can be seen microscopically in synovial sarcoma. One fibrous type, known as a spindle or sarcomatous cell, is relatively small and uniform, and found in sheets. The other is epithelial in appearance. Classical synovial sarcoma has a biphasic appearance with both types present. Synovial sarcoma can also appear to be poorly differentiated or to be monophasic fibrous, consisting only of sheets of spindle cells. Some authorities state that, extremely rarely, there can be a monophasic epithelial form which causes difficulty in differential diagnosis. Depending on the site, there is similarity to biphenotypic sinonasal sarcoma, although the genetic findings are distinctive.

Like other soft tissue sarcomas, there is no universal grading system for reporting histopathology results. In Europe, the Trojani or French system is gaining in popularity while the NCI grading system is more common in the United States. The Trojani system scores the sample, depending on tumour differentiation, mitotic index, and tumour necrosis, between 0 and 6 and then converts this into a grade of between 1 and 3, with 1 representing a less aggressive tumour. The NCI system is also a three-grade one, but takes a number of other factors into account.

For surface epithelial-stromal tumors, the most common sites of metastasis are the pleural cavity (33%), the liver (26%), and the lungs (3%).

In the older literature survival rates have been given as 35–50% for Stage I–II and 0–15% for Stage III and IV UPSC, More recently it was reported that forty-two percent of 138 patients were found disease-free at five years.

In 2009, the journal of "Gynecologic Oncology" reported the following 5-year survival rates based upon stage of cancer:

- Stage I: 50% - 80%

- Stage II: 50%

- Stage III: 20%

- Stage IV: 5% - 10%

On conventional radiographs, the most common osseous presentation is a permeative lytic lesion with periosteal reaction. The classic description of lamellated or "onion-skin" type periosteal reaction is often associated with this lesion. Plain films add valuable information in the initial evaluation or screening. The wide zone of transition (e.g. permeative) is the most useful plain film characteristic in differentiation of benign versus aggressive or malignant lytic lesions.

Magnetic resonance imaging (MRI) should be routinely used in the work-up of malignant tumors. It will show the full bony and soft tissue extent and relate the tumor to other nearby anatomic structures (e.g. vessels). Gadolinium contrast is not necessary as it does not give additional information over noncontrast studies, though some current researchers argue that dynamic, contrast-enhanced MRI may help determine the amount of necrosis within the tumor, thus help in determining response to treatment prior to surgery.

Computed axial tomography(CT) can also be used to define the extraosseous extent of the tumor, especially in the skull, spine, ribs, and pelvis. Both CT and MRI can be used to follow response to radiation and/or chemotherapy. Bone scintigraphy can also be used to follow tumor response to therapy.

In the group of malignant small round cell tumors which include Ewing's sarcoma, bone lymphoma, and small cell osteosarcoma, the cortex may appear almost normal radiographically, while permeative growth occurs throughout the Haversian channels. These tumours may be accompanied by a large soft-tissue mass while almost no bone destruction is visible. The radiographs frequently do not shown any signs of cortical destruction.

Radiographically, Ewing's sarcoma presents as "moth-eaten" destructive radiolucencies of the medulla and erosion of the cortex with expansion.

Prognosis of the UPSC is affected by age, stage, and histology as well as treatment.

In addition to being named based on the tissue of origin, sarcomas are also assigned a grade (low, intermediate, or high) based on the presence and frequency of certain cellular and subcellular characteristics associated with malignant biological behavior. Low grade sarcomas are usually treated surgically, although sometimes radiation therapy or chemotherapy are used. Intermediate and high grade sarcomas are more frequently treated with a combination of surgery, chemotherapy and/or radiation therapy. Since higher grade tumors are more likely to undergo metastasis (invasion and spread to locoregional and distant sites), they are treated more aggressively. The recognition that many sarcomas are sensitive to chemotherapy has dramatically improved the survival of patients. For example, in the era before chemotherapy, long-term survival for patients with localized osteosarcoma was only approximately 20%, but now has risen to 60–70%.

Sarcomas are given a number of different names based on the type of tissue that they most closely resemble. For example, osteosarcoma resembles bone, chondrosarcoma resembles cartilage, liposarcoma resembles fat, and leiomyosarcoma resembles smooth muscle.

Other entities with similar clinical presentations include osteomyelitis, osteosarcoma (especially telangiectatic osteosarcoma), and eosinophilic granuloma. Soft-tissue neoplasms such as pleomorphic undifferentiated sarcoma (malignant fibrous histiocytoma) that erode into adjacent bone may also have a similar appearance.

A retrospective study of 83 women with sex cord–stromal tumours (73 with granulosa cell tumour and 10 with Sertoli-Leydig cell tumour), all diagnosed between 1975 and 2003, reported that survival was higher with age under 50, smaller tumour size, and absence of residual disease. The study found no effect of chemotherapy. A retrospective study of 67 children and adolescents reported some benefit of cisplatin-based chemotherapy.

For more general information, see ovarian cancer.

For advanced cancer of this histology, the US National Cancer Institute recommends a method of chemotherapy that combines intravenous (IV) and intraperitoneal (IP) administration. Preferred chemotherapeutic agents include a platinum drug with a taxane.

There is no simple and reliable way to test for ovarian cancer in women who do not have any signs or symptoms. The Pap test does not screen for ovarian cancer.

Screening is not recommended in women who are at average risk, as evidence does not support a reduction in death and the high rate of false positive tests may lead to unneeded surgery, which is accompanied by its own risks.

Ovarian cancer is usually only palpable in advanced stages. Screening is not recommended using CA-125 measurements, HE4 levels, ultrasound, or adnexal palpation in women who are at average risk. Risk of developing ovarian cancer in those with genetic factors can be reduced. Those with a genetic predisposition may benefit from screening. This high risk group has benefited with earlier detection.

Ovarian cancer has low prevalence, even in the high-risk group of women from the ages of 50 to 60 (about one in 2000), and screening of women with average risk is more likely to give ambiguous results than detect a problem which requires treatment. Because ambiguous results are more likely than detection of a treatable problem, and because the usual response to ambiguous results is invasive interventions, in women of average risk, the potential harms of having screening without an indication outweigh the potential benefits. The purpose of screening is to diagnose ovarian cancer at an early stage, when it is more likely to be treated successfully.

Screening with transvaginal ultrasound, pelvic examination, and CA-125 levels can be used instead of preventative surgery in women who have BRCA1 or BRCA2 mutations. This strategy has shown some success.

Diagnosis of EIN lesions is of clinical importance because of the increased risk of coexisting (39% of women with EIN will be diagnosed with carcinoma within one year) or future (the long term endometrial cancer risk is 45 times greater for a woman with EIN compared to one with only a benign endometrial histology) endometrial cancer. Diagnostic terminology is that used by pathologists, physicians who diagnose human disease by examination of histologic preparations of excised tissues. Critical distinctions in EIN diagnosis are separation from benign conditions such as benign endometrial hyperplasia (a field effect in endometrial tissue caused by excessive stimulation by the hormone estrogen), and cancer.

The spectrum of disease which must be distinguished from EIN (Table II) includes benign endometrial hyperplasia and carcinoma:

Table II: Disease classes that need to be distinguished from EIN.

EIN may be diagnosed by a trained pathologist by examination of tissue sections of the endometrium. All of the following diagnostic criteria must be met in a single area of one tissue fragment to make the diagnosis (Table III).

Table III: EIN diagnosis.

In general, treatment for soft-tissue sarcomas depends on the stage of the cancer. The stage of the sarcoma is based on the size and grade of the tumor, and whether the cancer has spread to the lymph nodes or other parts of the body (metastasized). Treatment options for soft-tissue sarcomas include surgery, radiation therapy, and chemotherapy.

- Surgery is the most common treatment for soft-tissue sarcomas. If possible, the doctor will remove the cancer and a safe margin of the healthy tissue around it. It is important to obtain a margin free of tumor to decrease the likelihood of local recurrence and give the best chance for eradication of the tumor. Depending on the size and location of the sarcoma, it may, rarely, be necessary to remove all or part of an arm or leg.

- Radiation therapy may be used either before surgery to shrink tumors or after surgery to kill any cancer cells that may have been left behind. In some cases, it can be used to treat tumours that cannot be surgically removed. In multiple studies, radiation therapy has been found to improve the rate of local control, but has not had any influence on overall survival.

- Chemotherapy may be used with radiation therapy either before or after surgery to try to shrink the tumor or kill any remaining cancer cells. The use of chemotherapy to prevent the spread of soft-tissue sarcomas has not been proven to be effective. If the cancer has spread to other areas of the body, chemotherapy may be used to shrink tumors and reduce the pain and discomfort they cause, but is unlikely to eradicate the disease.

Phyllodes tumors are considered to be on a spectrum of disease that consists of fibroadenoma, fibroadenoma variant and benign phyllodes. Some would extend the spectrum to include malignant phyllodes tumors and frank sarcoma.

The common treatment for phyllodes is wide local excision. Other than surgery, there is no cure for phyllodes, as chemotherapy and radiation therapy are not effective. The risk of developing local recurrence or metastases is related to the histologic grade, according to the above-named features. Despite wide excision, a very high percentage of surgeries yielded incomplete excision margins that required revision surgery. Radiation treatment after breast-conserving surgery with negative margins may significantly reduce the

local recurrence rate for borderline and malignant tumors. The authors of a 2012 study have derived a risk calculator for relapse risk of phyllodes tumors after surgery.

Routine screening of asymptomatic people is not indicated, since the disease is highly curable in its early, symptomatic stages. Instead, women, particularly menopausal women, should be aware of the symptoms and risk factors of endometrial cancer. A cervical screening test, such as a Pap smear, is not a useful diagnostic tool for endometrial cancer because the smear will be normal 50% of the time. A Pap smear can detect disease that has spread to the cervix. Results from a pelvic examination are frequently normal, especially in the early stages of disease. Changes in the size, shape or consistency of the uterus and/or its surrounding, supporting structures may exist when the disease is more advanced. Cervical stenosis, the narrowing of the cervical opening, is a sign of endometrial cancer when pus or blood is found collected in the uterus (pyometra or hematometra).

Women with Lynch syndrome should begin to have annual biopsy screening at the age of 35. Some women with Lynch syndrome elect to have a prophylactic hysterectomy and salpingo-oophorectomy to greatly reduce the risk of endometrial and ovarian cancer.

Transvaginal ultrasound to examine the endometrial thickness in women with postmenopausal bleeding is increasingly being used to aid in the diagnosis of endometrial cancer in the United States. In the United Kingdom, both an endometrial biopsy and a transvaginal ultrasound used in conjunction are the standard of care for diagnosing endometrial cancer. The homogeneity of the tissue visible on transvaginal ultrasound can help to indicate whether the thickness is cancerous. Ultrasound findings alone are not conclusive in cases of endometrial cancer, so another screening method (for example endometrial biopsy) must be used in conjunction. Other imaging studies are of limited use. CT scans are used for preoperative imaging of tumors that appear advanced on physical exam or have a high-risk subtype (at high risk of metastasis). They can also be used to investigate extrapelvic disease. An MRI can be of some use in determining if the cancer has spread to the cervix or if it is an endocervical adenocarcinoma. MRI is also useful for examining the nearby lymph nodes.

Dilation and curettage or an endometrial biopsy are used to obtain a tissue sample for histological examination. Endometrial biopsy is the less invasive option, but it may not give conclusive results every time. Hysteroscopy only shows the gross anatomy of the endometrium, which is often not indicative of cancer, and is therefore not used, unless in conjunction with a biopsy. Hysteroscopy can be used to confirm a diagnosis of cancer. New evidence shows that D&C has a higher false negative rate than endometrial biopsy.

Before treatment is begun, several other investigations are recommended. These include a chest x-ray, liver function tests, kidney function tests, and a test for levels of CA-125, a tumor marker that can be elevated in endometrial cancer.

Definitive diagnosis of these tumours is based on the histology of tissue obtained in a biopsy or surgical resection. In a retrospective study of 72 cases in children and adolescents, the histology was important to prognosis.

A number of molecules have been proposed as markers for this group of tumours. CD56 may be useful for distinguishing sex cord–stromal tumours from some other types of tumours, although it does not distinguish them from neuroendocrine tumours. Calretinin has also been suggested as a marker. For diagnosis of granulosa cell tumour, inhibin is under investigation.

On magnetic resonance imaging, a fibroma may produce one of several imaging features that might be used in the future to identify this rare tumour prior to surgery.

When the tumor is large and there is presence of necrosis and local recurrence, the prognosis is poor. Presence of metastasis occurs in more than 50% cases and the common places of its occurrence are the bone, lymph node and lungs. Five-year survival rates, which are reported to be between 50-65%, can be misleading because the disease is prone to late metastasis or recurrence. Ten and twenty-year survival rates are 33% and 10%, respectively.

Endometrial stromal sarcoma is a malignant subtype of endometrial stromal tumor arising from the stroma (connective tissue) of the endometrium rather than the glands. There are three grades for endometrial stromal tumors, as follows. It was previously known as "endolymphatic stromal myosis" because of diffuse infiltration of myometrial tissue or the invasion of lymphatic channels.

The disease used to be uniformly fatal, with a 5-year survival rate between 10 and 35%. As a result, treatment was radical surgery. New multidrug chemotherapy regimens with or without radiation therapy are now used in combination with less radical surgery with good results, although outcome data are not yet available.