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

• Primary Osteogenic Renal Sarcoma
• Primary Renal Osteosarcoma

What is Primary Osteosarcoma of Kidney? (Definition/Background Information)

• Osteosarcoma forms a class of highly-cancerous, high-mortality, bone tumor. After multiple myeloma, it is the second-most common primary tumor of the bones. An extraskeletal osteosarcoma (EO) involves regions outside the bones
• Primary Osteosarcoma of Kidney is a rare, aggressive form of kidney cancer. It is an extraskeletal osteosarcoma. The tumor is observed in both children and adults. Of the different subtypes of osteosarcoma, the pleomorphic variant is the most common type observed in the kidney
• However, for the tumor to be called ‘primary’, the tumor must arise from kidney tissue, there must be no osteosarcoma present anywhere else in the body, and the sarcomatoid variant of renal cell carcinoma needs to be excluded
• The risk factors for carcinoma development are unidentified. However, the general risk factors for kidney cancers include a family history of kidney cancer, smoking, exposure to toxins, high blood pressure, obesity, and other factors
• The signs and symptoms of Primary Osteosarcoma of Kidney may include blood in urine, a lump on the side of the abdomen, flank pain, unexplained fever, and unexplained weight loss. It can give rise to complication such as the spread of cancer to other parts of the body (metastasis)
• The treatment options include surgery, radiation therapy, chemotherapy, and targeted drug therapy. The prognosis of Primary Osteosarcoma of Kidney depends on size of tumor and whether it is localized in the kidney or has metastasized (if it is an early or advanced stage, at the time of diagnosis). However, despite adequate treatment, the prognosis is usually poor

Who gets Primary Osteosarcoma of Kidney? (Age and Sex Distribution)

• Primary Osteosarcoma of Kidney may be seen in individuals of all age groups (children and adults). However, most cases are observed in the middle-aged and older age group (50-70 years)
• Even though both males and females are affected, a male preference is noted (male-female ratio is 2:1)
• The cancer is not specific to any ethnic or racial group
• Renal Osteosarcomas are very rare sarcomas (types of malignancies) and much less than 50 cases have been recorded worldwide

What are the Risk Factors for Primary Osteosarcoma of Kidney? (Predisposing Factors)

No clearly established risk factors are noted for Primary Osteosarcoma of Kidney. However, osteosarcoma risks, in general, are linked to the following factors:

• Some genetic mutations are associated with osteosarcoma; including mutations in Rb gene and P53
• Individuals with bilateral retinoblastoma have a higher risk for developing the condition
• A previously performed radiotherapy for other cancer conditions is an important risk factor - the tumor may be radiation-induced. The radiation has an expected side effect of damaging the genetic material in the normal cells. This can lead to the development of a “secondary” cancer
• Few genetic disorders, such as Rothmund-Thompson syndrome, Bloom’s syndrome, Li-Fraumeni syndrome, hereditary multiple exostosis, and Werner syndrome, have been associated with osteosarcoma
• Paget’s disease of the bone, fibrous dysplasia, osteoblastoma, Ollier disease, and chemotherapy, are other conditions that are believed to be associated with osteosarcomas
• Any physical injury or trauma

Some studies have shown that the following factors may predispose an individual to kidney cancer development:

• Family history of kidney cancer: If the cancer is present among close family members, then the risk of developing the cancer is increased
• Obesity
• High blood pressure
• Smoking
• Exposure to toxins, such as naphthylamine dye, asbestos, lead, polycyclic aromatic hydrocarbons, cadmium, and other chemical compounds
• Continuous use of certain medications such as non-steroidal anti-inflammatory drugs
• Long-term dialysis

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 health care provider.

What are the Causes of Primary Osteosarcoma of Kidney? (Etiology)

Currently, the definitive factor(s) causing Primary Osteosarcoma of Kidney is unidentified, but the tumor may be the result of certain genetic mutations. Researchers believe that the tumor arises from undifferentiated cells of primitive mesenchyme of kidney.

• The tumor can occur de novo or spontaneously, termed as a primary osteosarcoma (90% tumors occur spontaneously); or, due to some preexisting conditions and abnormalities, termed as a secondary osteosarcoma (about 10% tumors have an identified risk factor)
• Such preexisting conditions could include radiation-exposure, genetic anomalies, the presence of multiple chondroma, and any well-established physical injury or trauma
• A radiation-influenced tumor takes many years to develop, after the radiation exposure has ceased. The radiation may have been previously administered for treating other cancers

In general, it is known that cancers form when normal, healthy cells begin transforming into abnormal cells - these cancer cells grow and divide uncontrollably (and lose their ability to die), resulting in the formation of a mass or a tumor.

• The transformation of normally healthy cells into cancerous cells may be the result of genetic mutations. Mutations allow the cancer cells to grow and multiply uncontrollably to form new cancer cells
• These tumors can invade nearby tissues and adjoining body organs, and even metastasize and spread to other regions of the body

What are the Signs and Symptoms of Primary Osteosarcoma of Kidney?

The signs and symptoms associated with Primary Osteosarcoma of Kidney may include:

• Blood in the urine (hematuria)
• Fatigue due to anemia
• A visible lump may be seen on the side of the abdomen
• Fluid accumulation in the lower legs (pedal edema)
• The tumor can vary in size from a few mm to several cm
• Flank pain
• Unexplained weight loss
• Night sweats, unexplained fever
• Generalized weakness and pain in the body
• Abnormal liver function test
• If the tumor is associated with paraneoplastic syndrome; then, the following may be noted:
  • Increased blood pressure (hypertension)
  • Increased calcium in blood (hypercalcemia)
  • Increased red blood cells (erythrocytosis)
  • Increased platelets (thrombocytosis)
• Small-sized tumors may be asymptomatic

The signs and symptoms may depend on the size of the kidney tumor. The combination of signs and symptoms may also vary from individual to individual.

How is Primary Osteosarcoma of Kidney Diagnosed?

A healthcare provider might employ one or several of the following tools to diagnose Primary Osteosarcoma of Kidney tumors:

• Evaluation of the patient’s personal and family medical history
• A complete physical examination
• Blood tests such as complete blood count (CBC), serum calcium, serum albumin, liver function test (LFT), etc.
• Urine analysis such as albumin levels
• Plain X-ray of the abdomen
• Ultrasound scan of the abdomen
• Computed tomography (CT) scans of the kidneys
• Magnetic resonance imaging (MRI) and positron emission tomography (PET) scans may help differentiate benign versus malignant tumors by detecting areas of metastasis (if any)

Although the above modalities can be used to make the initial diagnosis, a tissue biopsy of the tumor may be required to make a definitive diagnosis to begin treatment.

• The tissue for diagnosis can be procured in multiple different ways, and they 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
  • Core biopsy of the tumor
  • Open biopsy of the tumor
• 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
• A differential diagnosis for Primary Osteosarcoma of Kidney may be undertaken to exclude the following tumors:
  • Adult Wilms tumor
  • Metastasis of osteosarcoma to the kidney
  • Metastatic sarcoma to kidneys
  • Sarcomatoid renal cell carcinoma
  • Sarcomatoid urothelial carcinoma of renal pelvis

Note:

• Radiological studies of the tumor specimen may reveal calcification
• Extensive tumor sampling during pathological examination is important to arrive at a definitive diagnosis
• Over 90% of the reported cases were diagnosed after tumor metastasis had occurred
• Of the different types of osteosarcoma, pleomorphic osteosarcoma is the most common type observed (in 40% of the cases). Apart from this, the osteoblastic and chondroblastic variants have also been recorded

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 Primary Osteosarcoma of Kidney?

The possible complications associated with Primary Osteosarcoma of Kidney include:

• The rarity of the condition may cause a delayed diagnosis leading to metastasis
• Metastasis: The cancer can spread to other areas of the body, since it is an aggressive tumor. The organs involved can include the abdominal cavity (peritoneum), liver and spleen, lungs, bone marrow, skin, and brain
• Recurrence of the tumor due to its partial or incomplete surgical removal
• Complications due to surgery
• Side effects of chemotherapy (such as toxicity) and radiation

How is Primary Osteosarcoma of Kidney Treated?

There are no established treatment guidelines, since a Renal Osteosarcoma is a very rare entity. Nevertheless, the treatment measures for Primary Osteosarcoma of Kidney may include the following:

• Surgery:
  • In majority of individuals, surgical resection of the tumor with clear margins may result in a cure, especially if the tumor is confined to the kidney. In some cases, due to location of the tumor, a complete surgical removal may be difficult
  • Several different surgical procedures may be available, such as partial/radical nephrectomy or laparoscopic surgery, depending on the type, size, and location of the tumor
  • Postoperative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Radiation therapy:
  • Radiotherapy can be used as primary therapy in situations where the tumor cannot be removed completely, or when the tumor reappears (recurrent osteosarcoma) after surgery
  • Radiotherapy can also be used as an additional therapy after surgery, if there is a possibility of tumor recurrence after surgery, or if there are inadequate margins following surgery (possibility of tumor left behind)
• Chemotherapy can be used for treating Primary Osteosarcoma of Kidney under the following circumstances (depending on case by case basis):
  • The tumor cannot be removed completely (incomplete surgical resection)
  • Tumors that recur after surgery 
  • Tumors that have spread to distant parts of the body (metastatic osteosarcoma)
• Immunotherapy: A patient’s immune system is activated to combat the cancer in this kind of therapy.
• Targeted drug therapy: This kind of drug treatment targets and kills cancer cells specifically, not harming surrounding normal/healthy cells

A long-term follow-up is required, because recurrence of the tumor at the site of surgery or metastasis in distant sites have been reported many years after surgery.

How can Primary Osteosarcoma of Kidney be Prevented?

Current medical research has not established a method of preventing Primary Osteosarcoma of Kidney.

• Regular health check-ups might help those individuals with a history of the condition in the immediate family and help diagnose the sarcoma early
• Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations for those who have already endured the tumor are helpful

In general, preventive methods for kidney cancers include reducing contributory risk factors, such as:

• Smoking
• Unhealthy diet and lifestyle
• Obesity
• Exposure to toxins
• Unnecessary medication

What is the Prognosis for Primary Osteosarcoma of Kidney? (Outcomes/Resolutions)

The prognosis of Primary Osteosarcoma of Kidney depends on the size of the tumor, their localization, and spread. In general, the prognosis is poor, since the tumors are aggressive malignancies. A mean survival period of 15 months is reported (range 8-22 months).

• Typically, the prognosis 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 better with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor. In majority of cases, the tumor is low stage
  • The surgical resectability 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
• When Primary Osteosarcoma of Kidney is diagnosed in the initial stages, the possibility of survival increases and the prognosis is considered good with treatment
• In cases where both kidneys are affected, the prognosis is not projected to be favorable. Additionally, if the cancer has spread to other parts of the body, such as to the liver, lungs, or bone, the possibility of prolonged survival following diagnosis is limited

As with any tumor, it is important to have follow-up appointments with a physician to monitor for any returning tumors.

Additional and Relevant Useful Information for Primary Osteosarcoma of Kidney:

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

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