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

• Phosphaturic Mesenchymal Tumor, Mixed Connective Tissue Type
• Phosphaturic Mesenchymal Tumour
• PMT (Phosphaturic Mesenchymal Tumor)

What is Phosphaturic Mesenchymal Tumor? (Definition/Background Information)

• Phosphaturic Mesenchymal Tumor (PMT) is an extremely infrequent tumor of the soft tissues and bones that results in tumor-induced osteomalacia (or TIO). The tumor is commonly seen during middle-age
• Osteomalacia is a deficiency disorder that causes weakening and softening of the bones, due to deficiency of calcium and vitamin D in the body. Longstanding osteomalacia may lead to severe bone abnormalities, stunted growth, and pathologic fractures
• The tumor appears as a solitary mass that can grow to fairly large sizes, anywhere in the body. Phosphaturic Mesenchymal Tumors are not generally known to cause pain and discomfort
• A complete surgical excision is used to treat Phosphaturic Mesenchymal Tumor. Following removal of the tumor, osteomalacia is known to resolve on its own
• The prognosis is generally excellent on adequate treatment; however, the chances of tumor recurrence is high (when incompletely removed). Also, while most tumors are benign, some are known to undergo malignant transformations

Who gets Phosphaturic Mesenchymal Tumor? (Age and Sex Distribution)

• Phosphaturic Mesenchymal Tumors are very rare tumors that are observed in middle-aged adults (mean age 53 years)
• However, they may be seen in individuals of a wide age range (up to age 80 years); even infants, young children, and elderly adults may be affected
• Both male and female genders are affected; though, a slight female preference is noted
• Currently, only about 300 cases of PMT have been recorded and no ethnic or racial preference is observed

What are the Risk Factors for Phosphaturic Mesenchymal Tumor? (Predisposing Factors)

• Presently, no risk factors have been specifically identified with regards to Phosphaturic Mesenchymal Tumor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s 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 Phosphaturic Mesenchymal Tumor? (Etiology)

• The exact cause and mechanism of Phosphaturic Mesenchymal Tumor formation is unknown
• The tumors may develop due to genetic abnormalities. But, further research is necessary to well-characterize the cause of tumor formation

Phosphaturic Mesenchymal Tumors produce a protein, called the fibroblast growth factor 23 (or FGF23), which induces osteomalacia in the affected individual.

What are the Signs and Symptoms of Phosphaturic Mesenchymal Tumor?

Phosphaturic Mesenchymal Tumor signs and symptoms may include:

• The tumors may be present as a mass in the soft tissues or bones, anywhere in the body
• The size of the tumor may range from 2-14 cm; however, most tumors are small and asymptomatic
• Retroperitoneal (abdominal cavity) and mediastinal (chest cavity) tumors, and tumors affecting the internal organs are very rarely noted
• The tumors result in osteomalacia, a condition that causes weak or soft bones
• Easy fractures, multiple fractures may occur due to weakening of bones
• A large number of tumors are benign; though, few tumors may be malignant

The signs and symptoms due to osteomalacia that may be present include:

• Muscle cramping and weak muscles
• Bone pain across the body
• Deformity of bones anywhere in the body
• Bowed legs
• Numbness in the limbs

How is Phosphaturic Mesenchymal Tumor Diagnosed?

A diagnosis of Phosphaturic Mesenchymal Tumor may involve the following tests and exams:

• Physical examination with comprehensive evaluation of the individual’s medical history
• Symptom assessment including evaluating the clinical features of long-term osteomalacia
• CT scan, MRI scan of the affected region
• Blood and urine tests including:
  • Complete blood count
  • Chemistry panel
  • Tests to determine the levels of calcium and phosphate in blood
  • Urinalysis to determine the levels of calcium and phosphate in urine
• Tissue biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination, who 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

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 Phosphaturic Mesenchymal Tumor?

The possible complications of Phosphaturic Mesenchymal Tumor may include the following:

• In children, the tumor may lead to stunted growth
• Weak bones are more prone to fractures from fall injuries
• Severe osteomalacia can cause skeletal deformities, particularly in children
• The diagnosed is often missed because of the rarity of the tumor, which can result in severe symptoms
• Damage to muscles, vital nerves, and blood vessels, during surgery
• Recurrence of PMT after surgery is known to take place quite frequently
• Extremely rarely, the tumors are known to undergo malignant transformations. Malignancy is known to mostly occur in tumors that return/recur

How is Phosphaturic Mesenchymal Tumor Treated?

Treatment measures for Phosphaturic Mesenchymal Tumor may include:

• A complete surgical excision of the tumor with removal of the entire lesion is the preferred method to treat the condition. If it is not fully removed, then the tumor is known to recur
• Typically, a complete surgical removal of the tumor is known to reverse the deficiency disorder (osteomalacia)
• Adequate supplementation through vitamin D and calcium
• Correcting the electrolyte imbalance, especially phosphate levels in the body
• Post-operative care is important: A minimum activity level is to be ensured, until the surgical wound heals
• Follow-up care with regular screening and check-ups are important and strongly advised

How can Phosphaturic Mesenchymal Tumor be Prevented?

• Current medical research has not established a way of preventing Phosphaturic Mesenchymal Tumor
• Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory for those who have already endured the tumor, due to its high recurrence rate and potential for malignancy

What is the Prognosis of Phosphaturic Mesenchymal Tumor? (Outcomes/Resolutions)

• The prognosis of Phosphaturic Mesenchymal Tumor is typically excellent with appropriate surgical intervention. A complete excision usually results in a low tumor recurrence rate
• Following removal of the tumor, osteomalacia is known to completely subside and resolve
• Occasionally, some tumors are known to undergo malignant transformations and few deaths have been reported

Additional and Relevant Useful Information for Phosphaturic Mesenchymal Tumor:

Please visit our Cancer & Benign Tumor Health Center for more physician-approved health information:

http://www.dovemed.com/diseases-conditions/cancer/