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

• Medullary Fibroma of Kidney
• Renal Hamartoma
• RMICT (Renomedullary Interstitial Cell Tumor)

What is Renomedullary Interstitial Cell Tumor? (Definition/Background Information)

• Renomedullary Interstitial Cell Tumor (RMICT) is a common benign tumor of the kidney that is usually discovered incidentally. The tumor is seen in a wide age range of adult individuals
• The kidney consists of 2 zones; the cortex and the medulla. The cortex is the peripheral or outer portion of the kidney, and the medulla is the central or inner portion of the kidney. The tumor may be present in the medulla of the kidney
• The signs and symptoms depend upon the size of the tumors and it may include blood in urine, abdominal pain, and frequent infections affecting the urinary tract system. Small tumors are mostly asymptomatic, while large tumors can cause chronic kidney failure
• Generally, no treatment is required for Renomedullary Interstitial Cell Tumor (for small and asymptomatic tumors). But, the healthcare provider may recommend regular follow-ups. The prognosis of the tumor is excellent, since it is a benign tumor

Who gets Renomedullary Interstitial Cell Tumor? (Age and Sex Distribution)

• Renomedullary Interstitial Cell Tumors are uncommon in the first 20 years of life. Thereafter, the incidence is known to increase with age
• Both males and females are affected and no predilection is noted
• No specific ethnic or racial preference is seen

What are the Risk Factors for Renomedullary Interstitial Cell Tumor? (Predisposing Factors)

• Currently, no definitive risk factors have been noted for Renomedullary Interstitial Cell 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 Renomedullary Interstitial Cell Tumor? (Etiology)

The exact cause and mechanism of Renomedullary Interstitial Cell Tumor formation is unknown.

What are the Signs and Symptoms for Renomedullary Interstitial Cell Tumor?

The signs and symptoms of Renomedullary Interstitial Cell Tumor depend on the size and location of the tumor. It can also vary from one individual to another. In general, small tumors are asymptomatic and large tumors can cause signs and symptoms. The kidney symptoms may be caused due to mass effect (presence of bulky tumors).

The signs and symptoms of RMICT may include the following:

• The tumor may be present as an abdominal mass
• It is often well- circumscribed tumor mass
• The tumors can range in size from a few mm to 8 cm
• Renomedullary Interstitial Cell Tumor are usually singe affecting one kidney; but, rarely they may be multiple and bilateral (affecting both kidneys)
• Some tumors may rarely cause an increase in blood pressure (BP)
• It may be associated with frequent urinary tract infections, blood in urine, and flank pain
• Large tumors can severely affect the functioning of the kidney that is involved. Tumors growing to larger sizes can cause compression of adjoining organs and structures, but are not known infiltrate into them.

How is Renomedullary Interstitial Cell Tumor Diagnosed?

In many cases, Renomedullary Interstitial Cell Tumor is diagnosed incidentally during imaging studies undertaken for some other health conditions. It is typically biopsied to rule-out cancer in some cases. Case reports indicate that the tumor is often detected during autopsies.

The diagnosis may involve the following tests and procedures:

• Complete physical exam with evaluation of medical history
• Complete blood counts with hematocrit (to detect polycythemia)
• Plain X-ray of the abdomen
• CT or CAT scan with contrast of the abdomen may show a well-defined mass. This radiological procedure creates detailed 3-dimensional images of structures inside the body
• 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
• Urine analysis to check for the presence of blood cells
• Kidney function test
• Intravenous pyelogram (IVP): A dye is injected into the blood vessels and the image of kidney structure is obtained
• Vascular angiographic studies of the tumor

Invasive diagnostic procedures such as:

• Laparoscopy: A special device is inserted through a small hole into the abdomen, to visually examine it. If necessary, a tissue sample is obtained for further analysis. Exploration of the abdomen using a laparoscope is called ‘exploratory laparoscopy’
• Laparotomy: The abdomen is opened through an incision for examination, and if required, a biopsy sample obtained. Exploration of the abdomen using laparotomy procedure is called ‘exploratory laparotomy’

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 kidney 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 kidney tumor
• Open biopsy of the kidney 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

A differential diagnosis, to eliminate other tumor types is considered, before arriving at a definitive diagnosis. The differential diagnosis includes:

• Metanephric stromal tumor
• Renal myxoma

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 Renomedullary Interstitial Cell Tumor?

The complications of Renomedullary Interstitial Cell Tumor may include:

• Stress and anxiety due to a concern of kidney cancer
• Chronic renal failure affecting kidney function if tumors are large is a potential complication
• The tumors can be multifocal and affect the function of both the kidneys
• If bleeding occurs in the tumor suddenly, it can cause retroperitoneal hemorrhage, which can result in large blood loss leading to severe shock. This is a potentially life-threatening complication requiring emergency care. In this situation, the signs and symptoms could be nausea, vomiting, back pain, sudden drop in blood pressure, and palpitations. This clinical condition is termed Wunderlich syndrome
• Damage to the muscles, vital nerves, and blood vessels, during surgery
• Post-surgical infection at the wound site is a potential complication

How is Renomedullary Interstitial Cell Tumor Treated?

The treatment options vary from one individual to another. The treatment measures for Renomedullary Interstitial Cell Tumor may include the following:

• Majority of asymptomatic tumors are not surgically removed after the tumor is determined to be benign on a biopsy: The healthcare provider may recommend a ‘wait and watch’ approach for small-sized tumors presenting mild signs and symptoms, after a diagnosis of RMICT is made
• Surgical intervention with complete excision can result in a complete cure. It can also help reduce the chances of tumor recurrence

The surgical treatment methods for Renomedullary Interstitial Cell Tumor may include:

• Endoscopic surgery
• Nephron-sparing surgery
• Partial or complete nephrectomy

A partial or complete nephrectomy may be considered, when large-sized tumors are noted in the kidneys. 

• A kidney dialysis may be required, if the kidney function is severely compromised due to renal failure
• Prompt diagnosis and emergency treatment of any abdominal (retroperitoneal) bleeding due to the tumor should be immediately considered
• Postoperative care is important: A minimum activity level is ensured, until the surgical wound heals
• Follow-up care with regular screening may be recommended by the healthcare provider

How can Renomedullary Interstitial Cell Tumor be Prevented?

• Current medical research has not established a method of preventing Renomedullary Interstitial Cell Tumor
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Renomedullary Interstitial Cell Tumor? (Outcomes/Resolutions)

• The prognosis of Renomedullary Interstitial Cell Tumor depends upon the severity of the signs and symptoms. It also depends upon the overall health of the individual and response to therapy
• In most cases, the prognosis is excellent, since these are benign

Additional and Relevant Useful Information for Renomedullary Interstitial Cell Tumor:

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

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