What are the other Names for this Condition? (Also known as/Synonyms)

• Seminal Vesicle SFT
• Seminal Vesicle Solitary Fibrous Tumor
• SFT of Seminal Vesicle 

What is Solitary Fibrous Tumor of Seminal Vesicle? (Definition/Background Information)

• Solitary Fibrous Tumor (SFT) of Seminal Vesicle is a mostly benign (non-cancerous) overgrowth arising from mesenchymal tissue
• The mesenchyme is the middle layer of the 3 primary germ layers of an embryo, namely the ectoderm, mesoderm, and endoderm. The mesoderm gives rise to mesenchymal tissue, which is the source for bone, muscle, connective tissue, and dermis of skin
• Solitary Fibrous Tumors are composed of fibroblasts and related cell types. These rare tumors can occur in any part of the body, or in the soft tissues, where mesenchymal cells are present. The tumor arises as a mass in the seminal vesicle gland (a male gland located near the urinary bladder in the pelvis)
• The cause of formation of the tumor is unknown and currently, no known methods exist to prevent occurrence of the tumor
• Most small tumors are asymptomatic, though the larger ones may compress the surrounding structures and cause related signs and symptoms. The diagnosis of Solitary Fibrous Tumor of Seminal Vesicle can be confirmed through a tissue biopsy
• The treatment is complete surgical removal of the tumor with adequate margins. Most Solitary Fibrous Tumors of Seminal Vesicle are benign, however some show malignant behavior in terms of recurrence of the tumor after surgery, or metastasis (spread to distant parts of the body)
• The prognosis of Solitary Fibrous Tumor of Seminal Vesicle is dependent on whether the tumor can be completely removed through surgery or not

Who gets Solitary Fibrous Tumor of Seminal Vesicle? (Age and Sex Distribution)

• The Solitary Fibrous Tumor of Seminal Vesicle can present be in men between 20 and 70 years of age, but is usually diagnosed in the fifth decade (between 40-50 years)
• Though it is a rare tumor, it can occur worldwide and all races and ethnic groups may be affected

What are the Risk Factors for Solitary Fibrous Tumor of Seminal Vesicle? (Predisposing Factors)

• No clear-cut risk factors for Solitary Fibrous Tumor of Seminal Vesicle have been established to date

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Solitary Fibrous Tumor of Seminal Vesicle? (Etiology)

• Currently, scientists do not know the factor(s) causing Solitary Fibrous Tumor of Seminal Vesicle
• Certain genetic mutations are have been detected. Research to characterize these mutations is currently underway

What are the Signs and Symptoms of Solitary Fibrous Tumor of Seminal Vesicle?

The signs and symptoms depend on the size of the tumor. Solitary Fibrous Tumors can range in size from a few cm to up to 40 cm; though majority of the seminal vesicle tumors are less than 10 cm in size. They are usually slow-growing and form a single mass. The signs and symptoms associated with Solitary Fibrous Tumor of Seminal Vesicle include:

• Small tumors usually do not cause any symptoms. But, occasionally they may become painful, if they compress surrounding structure
• Solitary Fibrous Tumors of Seminal Vesicle may occur as slowly enlarging painless mass. The following symptoms may be seen:
  • Frequent urination at night (nocturia)
  • Pain when urinating
  • Difficulty in urinating
  • Abdominal pain
• Rarely, these tumors, especially if large, may cause hypoglycemia
  • Hypoglycemia results in Doege-Potter syndrome, which occurs due to secretion of insulin-like growth factor-2 (IGF-2) by the tumor cells (paraneoplastic syndrome)
  • The signs and symptoms of hypoglycemia include confusion, altered mental status, sweating, dizziness, cold hands, etc.

How is Solitary Fibrous Tumor of Seminal Vesicle Diagnosed?

The following procedures and tools may be used in the diagnosis of Solitary Fibrous Tumor of Seminal Vesicle:

• Evaluation of the individual’s medical history and a through physical examination
• Digital rectal exam (DRE): During a DRE exam, a physician uses their fingers (using lubricated rubber gloves) to physically detect any abnormalities within the seminal vesicle
• Plain X-ray of the abdomen
• Computerized tomography (CT) scan of abdomen: This radiological procedure creates detailed three-dimensional images of structures inside the body. CT scans are not a tool of preference to detect the tumor
• CT scan with contrast of the abdomen usually shows a well defined mass in the seminal vesicle which may have calcifications
• MRI scans of the abdomen: Magnetic resonance imaging (MRI) uses a magnetic field to create high-quality pictures of certain parts of the body, such as tissues, muscles, nerves, and bones. These high-quality pictures may reveal the presence of the tumor
• Ultrasound scan of the abdomen
• Trans-rectal ultrasound (TRUS): In this diagnosis method, a tiny probe is inserted into the patient’s rectum, to take pictures of the seminal vesicle gland through emission of sound waves
• Solitary Fibrous Tumor of Seminal Vesicle can additionally be evaluated using angiography of the abdomen region
• MRI scans and PET scans may help differentiate benign versus malignant SFTs by detecting areas of metastasis (if any)

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include:

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred. Also, Solitary Fibrous Tumor is a fibrous tumor and FNA usually does not reveal many cells on microscopic examination.
• Core biopsy of the tumor (trans-rectal biopsy): During a trans-rectal biopsy, a special biopsy forceps is used to pass through the rectal wall into the seminal vesicle in order to collect small tissue samples from within the gland
• Open biopsy of the tumor

Tissue biopsy:

• A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Solitary Fibrous Tumor of Seminal Vesicle?

Complications due to Solitary Fibrous Tumor of Seminal Vesicle could include:

• Urinary incontinence is an embarrassing and distressing condition that causes the individual to have a loss of bladder function. It can be seen in patients who have endured treatments for SFT of Seminal Vesicle
• Erectile dysfunction (impotence) is a sexual dysfunction resulting from the inability of men to develop, or hold an erection during sexual intercourse, especially after tumor removal surgery
• Hypoglycemia resulting in Doege-Potter syndrome, which occurs due to secretion of insulin-like growth factor-2 (IGF-2) by the tumor cells
• Recurrence of SFT following surgery
• Malignant transformation resulting in metastatic SFT
• Complications may arise during chemotherapy and radiation therapy, due to the toxic medication or radiation effect

How is Solitary Fibrous Tumor of Seminal Vesicle Treated?

There is no standard treatment protocol established for Solitary Fibrous Tumor of Seminal Vesicle. However, in majority of cases, a complete surgical excision with clear or wide margins is the preferred mode of treatment, which can result in a cure, especially if it behaves in a benign manner.

• Surgery for Solitary Fibrous Tumor of Seminal Vesicle: The recommended surgical treatment for men involves a surgical removal of the seminal vesicle gland. The types of surgical treatments a physician may recommend include:
  • Radical retropubic prostatectomy and seminal vesiculectomy: Radical retropubic prostatectomy and seminal vesiculectomy is the surgical removal of the entire prostate gland and seminal vesicle, usually performed by a urologic oncologist. During this procedure, a surgeon removes the prostate gland, seminal vesicles, and the surrounding lymph nodes of the pelvis through a small incision in the abdomen. This surgery is used in cases, where the tumor is still centralized within the seminal vesicle gland
  • Radical perineal prostatectomy and seminal vesiculectomy: It is also the surgical removal of the entire prostate gland and seminal vesicle, usually performed by a urologic oncologist. The prostate gland is removed through a small incision between the anus and scrotum. Like radical retropubic prostatectomy and seminal vesiculectomy, a radical perineal prostatectomy and seminal vesiculectomy surgery is used, when the tumor is still contained within the seminal vesicle gland
  • Laparoscopic radical prostatectomy (LRP) and seminal vesiculectomy: During a LRP, an incision is made in the abdomen and using a laparoscope, the prostate gland and seminal vesicle is removed
  • Cryosurgery: It is a cryosurgical treatment, effective in treating early stages of Solitary Fibrous Tumor of Seminal Vesicle. Cryosurgery involves the use of liquid nitrogen to freeze cancer cells, by means of an instrument called a cryoprobe. The cryoprobe is inserted through a tiny incision between the scrotum and anus
  • High-frequency ultrasound (HIFUS): During a high frequency ultrasound procedure, a tiny probe is inserted through the rectum and into the seminal vesicle, precisely targeting the tumor cells, using ultrasound. HIFUS employs an extremely accurate medical instrument, which uses ultrasound to heat and eliminate tumor cells, within the Seminal Vesicle 
• Long-term follow-up is required, because recurrence at the site of surgery or metastasis in distant sites have been reported many years after surgery, even with tumors that behave benignly
• Radiotherapy can be used as primary therapy in situations where the tumor cannot be removed completely, or when the tumor reappears (recurrent Solitary Fibrous Tumor of Seminal Vesicle) after surgery. Radiation therapy attempts to destroy cancer cells by aiming high-energy beams at them. It can be administered either by a machine placed outside the body (external beam radiation), or by a device positioned inside the seminal vesicle (brachytherapy). The therapy may be used either before a surgery is proposed, so as to decrease the size of the tumor allowing for its easier removal, or after the surgery is performed, in order to kill any remaining cancer cells
• Radiotherapy for SFT can also be used as additional therapy after surgery, if there is a possibility of tumor recurrence after surgery, or if there are inadequate margins (possibility of tumor left behind) following surgery. In some cases due to location of tumor, a complete surgical removal of the tumor is difficult
• Chemotherapy can be used for treating Solitary Fibrous Tumor of Seminal Vesicle in following conditions:
  • When the tumors cannot be removed completely (due to incomplete surgical resection)
  • Tumors that recur after surgery (recurrent SFT of Seminal Vesicle)
  • Tumors that have spread to distant parts of the body (metastatic SFT of Seminal Vesicle)
• Arterial embolization of Solitary Fibrous Tumor of Seminal Vesicle is a possible treatment option. Here the blood supply to the tumor is blocked resulting in tumor death
• Hypoglycemia due to the tumor is treated using corticosteroids
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals

How can Solitary Fibrous Tumor of Seminal Vesicle be Prevented?

• Current medical research has not established a way of preventing Solitary Fibrous Tumor of Seminal Vesicle formation
• Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations, for those who have already endured the tumor, are helpful

What is the Prognosis of Solitary Fibrous Tumor of Seminal Vesicle? (Outcomes/Resolutions)

• The most reliable prognostic factor of Solitary Fibrous Tumor of Seminal Vesicle is dependent on whether the tumor can be completely removed through surgery with free margins (no traces of the tumor in adjoining tissue) or not
• Current studies show that the tumor does not have any specific histologic feature (when a pathologist examines the tissue under a microscope), which can help in assessing a definite prognosis for the tumor
• Individuals have an overall excellent survival rate following first complete surgical resection
• Solitary Fibrous Tumor of Seminal Vesicle that behave malignantly can lead to death
• As with any tumor, it is important to have follow-up appointments with a physician to monitor for any returning tumors

The prognosis of Solitary Fibrous Tumors also depends upon a set of several factors, which include:

• Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
• The surgical respectability of the tumor (meaning, if the tumor can be removed completely) 
• Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
• Age of the individual: Older individuals generally have poorer prognosis than younger individuals
• Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
• Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment

An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment.

Additional and Relevant Useful Information for Solitary Fibrous Tumor of Seminal Vesicle:

• A tumor is an abnormal growth of tissue arising due to uncontrolled and rapid multiplication of cells that serve no function. They are also called neoplasms. Tumors can be benign or cancerous. A benign tumor may generally indicate no threat to one’s health; it also means that it is not “cancerous”
• Grossly, Solitary Fibrous Tumor of Seminal Vesicle is well-circumscribed but not encapsulated, and on cross-section appears gray white to yellow white in color
• Microscopically, benign SFT exhibit alternation of hyper- and hypo- cellular areas, patternless pattern, keloid type collagen, and staghorn-shaped vessels-like areas
• A pathologist may use special studies such as special stains. Special stains (markers) used on biopsy samples may include CD34, CD99, Vimentin, BCL-2. These stains help differentiate Solitary Fibrous Tumors of Seminal Vesicle from other benign or cancer lesions
• Although Solitary Fibrous Tumor can be classified as malignant based on the biopsy study (tumor greater than 5 cm, increased mitotic rate, necrosis, increased cellularity, or cytologic atypia, infiltrative growth, and weak CD34), these features cannot be absolutely correlated with regards to how it behaves, the nature of which may be aggressive, metastasis, or recurrent
• Basic fibroblast growth factor (bFGF) labeling index and Ki-67 labeling index can be used for evaluation of benign versus malignant Solitary Fibrous Tumors of Seminal Vesicle
• Hemangiopericytoma (also known as Solitary Fibrous Tumor - Hemangiopericytoma type; or Cellular Solitary Fibrous Tumor) is closely related to SFT of Seminal Vesicle, but is not identical to it. Many pathologists consider hemangiopericytoma and Solitary Fibrous Tumor as a continuum of tumors