The treatment of choice for both benign and malignant SFT is complete "en bloc" surgical resection.

Prognosis in benign SFTs is excellent. About 8% will recur after first resection, with the recurrence usually cured after additional surgery.

The prognosis in malignant SFTs is much more guarded. Approximately 63% of patients will have a recurrence of their tumor, of which more than half will succumb to disease progression within 2 years. Adjuvant chemotherapy and/or radiotherapy in malignant SFT remains controversial.

Recurrent somatic fusions of the two genes, NGFI-A–binding protein 2 (NAB2) and STAT6, located at chromosomal region 12q13, have been identified in solitary fibrous tumors.

There are no known risk factors that have been identified specific to the disease. The tumor appears to arise from the primitive cells of childhood, and is considered a childhood cancer.

Research has indicated that there is a chimeric relationship between desmoplastic small-round-cell tumor (DSRCT) and Wilms' tumor and Ewing's sarcoma. Together with neuroblastoma and non-Hodgkin's lymphoma, they form the small cell tumors.

DSRCT is associated with a unique chromosomal translocation t(11;22)(p13:q12) resulting in an EWS/WT1 transcript that is diagnostic of this tumor. This transcript codes for a protein that acts as a transcriptional activator that fails to suppress tumor growth.

The EWS/WT1 translocation product targets ENT4. ENT4 is also known as PMAT.

The prognosis for DSRCT remains poor. Prognosis depends upon the stage of the cancer. Because the disease can be misdiagnosed or remain undetected, tumors frequently grow large within the abdomen and metastasize or seed to other parts of the body.

There is no known organ or area of origin. DSRCT can metastasize through lymph nodes or the blood stream. Sites of metastasis include the spleen, diaphragm, liver, large and small intestine, lungs, central nervous system, bones, uterus, bladder, genitals, abdominal cavity, and the brain.

A multi-modality approach of high-dose chemotherapy, aggressive surgical resection, radiation, and stem cell rescue improves survival for some patients. Reports have indicated that patients will initially respond to first line chemotherapy and treatment but that relapse is common.

Some patients in remission or with inoperable tumor seem to benefit from long term low dose chemotherapy, turning DSRCT into a chronic disease.

The primary method for treatment is surgical, not medical. Radiation and chemotherapy are not needed for benign lesions and are not effective for malignant lesions.

Benign granular cell tumors have a recurrence rate of 2% to 8% when resection margins are deemed clear of tumor infiltration. When the resection margins of a benign granular cell tumor are positive for tumor infiltration the recurrence rate is increased to 20%. Malignant lesions are aggressive and difficult to eradicate with surgery and have a recurrence rate of 32%.

Fertility subsequent to treatment of surface epithelial-stromal tumors depends mainly on histology and initial

staging to separate it into early borderline (or more benign) versus advanced stages of borderline (or more malignant). Conservative management (without bilateral oophorectomy) of early stage borderline tumors have been estimated to result in chance of over 50% of spontaneous pregnancy with a low risk of lethal recurrence of the tumor (0.5%). On the other hand, in cases of conservative treatment in advanced stage borderline tumors, spontaneous pregnancy rates have been estimated to be 35% and the risk of lethal recurrence 2%.

Surface epithelial-stromal tumors are a class of ovarian neoplasms that may be benign or malignant. Neoplasms in this group are thought to be derived from the ovarian surface epithelium (modified peritoneum) or from endometrial or Fallopian tube (tubal) tissue. Tumors of this type are also called ovarian adenocarcinoma. This group of tumors accounts for 90% to 95% of all cases of ovarian cancer. Serum CA-125 is often elevated but is only 50% accurate so it is not a useful tumor marker to assess the progress of treatment.

Giant-cell tumor of the bone accounts for 4-5% of primary bone tumors and about 20% of benign bone tumors. However, significantly higher incidence rates are observed in Asia, where it constitutes about 20% of all primary bone tumors in China. It is slightly more common in females, has a predilection for the epiphyseal/metaphyseal region of long bones, and generally occurs in the third to fourth decade. Although classified as a benign tumor, GCTOB has been observed to metastesize to the lungs in up to 5% of cases, and in rare instances (1-3%) can transform to the malignant sarcoma phenotype with equal disease outcome.

Ovarian tumors, or ovarian neoplasms, are tumors arising from the ovary. They can be benign or malignant (ovarian cancer).

Granular cell tumor is a tumor that can develop on any skin or mucosal surface, but occurs on the tongue 40% of the time.

It is also known as Abrikossoff's tumor, Granular cell myoblastoma, Granular cell nerve sheath tumor, and Granular cell schwannoma.)

A number of tumors have giant cells, but are not true benign giant-cell tumors. These include, aneurysmal bone cyst, chondroblastoma, simple bone cyst, osteoid osteoma, osteoblastoma, osteosarcoma, giant-cell reparative granuloma, and brown tumor of hyperparathyroidism.

A benign tumor is a mass of cells (tumor) that lacks the ability to invade neighboring tissue or metastasize. Benign tumors do not spread into, or invade, nearby tissues. Benign tumors can sometimes be quite large, however. When removed, they usually do not grow back, whereas malignant tumors sometimes do. Unlike most benign tumors elsewhere in the body, benign brain tumors can be life threatening. Benign tumors generally have a slower growth rate than malignant tumors and the tumor cells are usually more differentiated (cells have normal features). Benign tumors are typically surrounded by an outer surface (fibrous sheath of connective tissue) or remain with the epithelium. Common examples of benign tumors include moles and uterine fibroids.

Although benign tumors will not metastasize or locally invade tissues, some types may still produce negative health effects. The growth of benign tumors produces a "mass effect" that can compress tissues and may cause nerve damage, reduction of blood to an area of the body (ischaemia), tissue death (necrosis) and organ damage. The mass effect of tumors is more prominent if the tumor is within an enclosed space such as the cranium, respiratory tract, sinus or inside bones. Tumors of endocrine tissues may overproduce certain hormones, especially when the cells are well differentiated. Examples include thyroid adenomas and adrenocortical adenomas.

Although most benign tumors are not life-threatening, many types of benign tumors have the potential to become cancerous (malignant) through a process known as tumour progression. For this reason and other possible negative health effects, some benign tumors are removed by surgery.

Benign tumors of the ovary include ovarian cysts, such as borderline tumor cysts.

Eye neoplasms can affect all parts of the eye, and can be a benign tumor or a malignant tumor (cancer). Eye cancers can be primary (starts within the eye) or metastatic cancer (spread to the eye from another organ). The two most common cancers that spread to the eye from another organ are breast cancer and lung cancer. Other less common sites of origin include the prostate, kidney, thyroid, skin, colon and blood or bone marrow.

Tumors in the eye and orbit can be benign like dermoid cysts, or malignant like rhabdomyosarcoma and retinoblastoma.

Pleomorphic adenoma is a common benign salivary gland neoplasm characterised by neoplastic proliferation of parenchymatous glandular cells along with myoepithelial components, having a malignant potentiality. It is the most common type of salivary gland tumor and the most common tumor of the parotid gland. It derives its name from the architectural Pleomorphism (variable appearance) seen by light microscopy. It is also known as "Mixed tumor, salivary gland type", which describes its pleomorphic appearance as opposed to its dual origin from epithelial and myoepithelial elements.

Mucinous cystadenoma is a benign cystic tumor lined by a mucinous epithelium. It is a type of cystic adenoma (cystadenoma).

Mucinous cystadenoma may arise in a number of locations; however, mucinous cystadenoma at different locations are not generally considered to be related to one another.

Leiomyoma is the most common benign mesenchymal tumor of esophagus and second most common benign tumor of the small bowel (with gastrointestinal stromal tumor as most common). Although leiomyoma is the most common benign esophageal tumor, malignant carcinoma is still 50 times more likely. Approximately 50% of cases are found in the jejunum, followed by the ileum in 31% of cases. Almost one half of all lesions are less than 5 centimeters.

The average age at time of EIN diagnosis is approximately 52 years, compared to approximately 61 years for carcinoma. The timeframe and likelihood of EIN progression to cancer, however, is not constant amongst all women. Some cases of EIN are first detected as residual premalignant disease in women who already have carcinoma, whereas other EIN lesions disappear entirely and never lead to cancer. For this reason, treatment benefits and risks must be individualized for each patient under the guidance of an experienced physician.

Risk factors for development of EIN and the endometrioid type of endometrial carcinoma include exposure to estrogens without opposing progestins, obesity, diabetes, and rare hereditary conditions such as hereditary nonpolyposis colorectal cancer. Protective factors include use of combined oral contraceptive pills (low dose estrogen and progestin), and prior use of a contraceptive intrauterine device.

Benign tumors are very diverse, and may be asymptomatic or may cause specific symptoms depending on their anatomic location and tissue type. They grow outwards, producing large rounded masses, which can cause what is known as a "mass effect". This growth can cause compression of local tissues or organs, which can cause many effects such as blockage of ducts, reduced blood flow (ischaemia), tissue death (necrosis) and nerve pain or damage. Some tumors also produce hormones that can lead to life-threatening situations. Insulinomas can produce large amounts of insulin leading to hypoglycemia. Pituitary adenomas can cause elevated levels of hormones such as growth hormone and insulin-like growth factor-1, which cause acromegaly; prolactin; ACTH and cortisol, which cause Cushings disease; TSH, which causes hyperthyroidism; and FSH and LH. Bowel intussusception can occur with various benign colonic tumors. Cosmetic effects can be caused by tumors, especially those of the skin, possibly causing psychological effects on the person with the tumor. Vascular tumors can bleed, which in some cases can be substantial, leading to anemia.

Lipoblastoma is a type of subcutaneous benign fatty tumor.

Types include:

- Benign lipoblastomatosis, a tumor, also known as an embryonic lipoma, which usually occurs in children under three years old. This is the tumor of brown fat cells.

- Myxoid lipoblastoma, a cutaneous condition characterized by excess mucin

Working with asbestos is the most common risk factor for mesothelioma. However, mesothelioma has been reported in some individuals without any known exposure to asbestos.

Treatment may include the following:

- Surgery with or without radiation

- Radiotherapy

Fast neutron therapy has been used successfully to treat salivary gland tumors, and has shown to be significantly more effective than photons in studies treating unresectable salivary gland tumors.

- Chemotherapy

Mesenchymal neoplasms of the gallbladder are rare and in particular leiomyomas of the gallbladder have been rarely reported, all of them in patients with immune system disorders. Although, recently, a case was reported in absence of associated immunodeficiency at Monash Hospital in Melbourne Australia in a healthy 39-year-old woman with no symptoms.

An oncocytoma is a tumor made up of oncocytes, epithelial cells characterized by an excessive amount of mitochondria, resulting in an abundant acidophilic, granular cytoplasm. The cells and the tumor that they compose are often benign but sometimes may be premalignant or malignant.