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

• Primary Thyroid-like Follicular RCC
• Thyroid-Like Follicular Carcinoma of Kidney (TLFCK)
• TLFCK (Thyroid-Like Follicular Carcinoma of Kidney)

What is Primary Thyroid-like Follicular Renal Cell Carcinoma? (Definition/Background Information)

• Primary Thyroid-like Follicular Renal Cell Carcinoma is a rare histological variant of renal cell carcinoma (RCC). The tumor resembles thyroid follicles on observation under a microscope, and hence the name
• It is a low-malignancy potential tumor that rarely metastasizes. The tumor is also commonly known as Thyroid-Like Follicular Carcinoma of Kidney (TLFCK)
• The exact cause of development of the tumor is presently unknown, but it may be due to genetic factors. The involvement of several chromosomes has been noted in various research studies
• The risk factors for developing Primary Thyroid-like Follicular Renal Cell Carcinoma are generally unknown. However, the factors that may contribute to the development of kidney cancers include a positive family history of kidney cancer, smoking, exposure to toxins, high blood pressure, and obesity
• The typical symptoms of Primary Thyroid-like Follicular Renal Cell Carcinoma include blood in urine, flank pain (in case of large tumors), unexplained fever, and unexplained weight loss
• Very rarely, it may give rise to complications such as spread of cancer to other parts of the body. The healthcare provider might diagnose Primary Thyroid-like Follicular Renal Cell Carcinoma using blood tests, imaging studies, and tissue biopsy, as necessary
• The treatment options include surgery, radiation therapy, chemotherapy, and targeted drug therapy. The prognosis of Primary Thyroid-like Follicular Renal Cell Carcinoma depends on the size of the tumor and whether it is localized in the kidney or has metastasized (i.e., if the disease is in its early or advanced stages, at the time of diagnosis). However, in most cases, the prognosis is good with suitable treatment
• It may not be possible to prevent tumor formation; although, in general, leading a healthy lifestyle, maintaining an ideal body weight, controlling one’s blood pressure, avoiding unnecessary medication, and avoiding smoking, are all factors that can potentially help one reduce the risk for cancer development

The main types of kidney cancers include:

• Clear cell renal cell carcinoma: This is also called conventional renal cell carcinoma. 65% of renal cancers belong to this type
• Papillary renal cell carcinoma (PRCC): It is also called chromophil renal cell carcinoma. It constitutes 15% of all renal cancers. Some of these cancers can be seen in syndromes such as hereditary papillary renal cell carcinoma syndrome. A majority of individuals with PRCC, do not have a family history of kidney cancer
• Chromophobe renal cell carcinoma: They make up for 5% of the renal cancers. Usually, it is a slower-growing cancer when compared to other kidney cancers
• Collecting duct carcinoma of kidney: They make up for approximately 1% of the kidney cancers. The cancer arises from the collecting ducts of the kidney

Who gets Primary Thyroid-like Follicular Renal Cell Carcinoma? (Age and Sex Distribution)

• Primary Thyroid-like Follicular Renal Cell Carcinoma is a very rare tumor that affects adult men and women in the 29-83 years age range (average age 34 years)
• A slight female preference is noted and the female-male ratio is 7:5
• The cancer is not specific to any ethnic or racial group

What are the Risk Factors for Primary Thyroid-like Follicular Renal Cell Carcinoma? (Predisposing Factors)

In a majority of individuals, no clear-cut risk factors for Primary Thyroid-like Follicular Renal Cell Carcinoma have been established to date. However, in general, 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 Thyroid-like Follicular Renal Cell Carcinoma? (Etiology)

Currently, scientists do not know the definitive factor(s) causing Primary Thyroid-like Follicular Renal Cell Carcinoma. However, research on the tumor has revealed the following abnormalities:

• Gains on chromosome 7, 8, 12, 16, 17, 19, 20, 21, and chromosome X
• Loss on chromosome 1, 3, 7, 9, 12, 17, and chromosome X

Research is underway to well-characterize these genetic abnormalities.

What are the Signs and Symptoms of Primary Thyroid-like Follicular Renal Cell Carcinoma?

The signs and symptoms associated with Primary Thyroid-like Follicular Renal Cell Carcinoma may include:

• Small tumors usually do not cause any symptoms. But, occasionally they may become painful, if they compress the surrounding structure
• Blood in the urine (hematuria)
• Fatigue due to anemia
• The tumor may range in size between 1-4 cm, but can grow larger (up to 12 cm in size noted)
• Fluid accumulation in the lower legs (pedal edema)
• Flank pain
• Unexplained weight loss
• Night sweats, unexplained fever
• Generalized weakness and pain in the body
• Abnormal liver function test

The signs and symptoms may depend on the size of the kidney tumor.

How is Primary Thyroid-like Follicular Renal Cell Carcinoma Diagnosed?

A healthcare provider might employ one or several of the following tools to diagnose Primary Thyroid-like Follicular Renal Cell Carcinoma:

• Evaluation of the individual’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 (LFTs), etc.
• Urine analysis such as albumin levels
• Plain X-ray of the abdomen
• Ultrasound scan of the abdomen (for liver metastasis)
• Computed tomography (CT) scans of the kidneys
• Magnetic resonance imaging (MRI) and positron emission tomography (PET) scans may help differentiate between 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, to eliminate other tumor types is considered, before arriving at a conclusion. These include:

• Carcinoid tumor of kidney
• Metablastic follicular carcinoma from struma ovarii in females
• Metastatic thyroid carcinoma to kidneys

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 Thyroid-like Follicular Renal Cell Carcinoma?

The possible complications associated with Primary Thyroid-like Follicular Renal Cell Carcinoma include:

• 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
• Metastasis: The cancer can spread to other areas of the body, such as to the regional lymph nodes and lung. However, spread of the cancer to other body sites is very rare
• Complications due to surgery
• Side effects of chemotherapy (such as toxicity) and radiation therapy

How is Primary Thyroid-like Follicular Renal Cell Carcinoma Treated?

The treatment measures Primary Thyroid-like Follicular Renal Cell Carcinoma 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 (inaccessibility), 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 Primary Thyroid-like Follicular Renal Cell Carcinoma) 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 Thyroid-like Follicular Renal Cell Carcinoma under the following circumstances (depending on case by case basis):
  • The tumor cannot be removed completely (incomplete surgical resection)
  • Tumors that recur after surgery (recurrent Primary Thyroid-like Follicular Renal Cell Carcinoma)
  • Tumors that have spread to distant parts of the body (metastatic Primary Thyroid-like Follicular Renal Cell Carcinoma)
• Arterial embolization of Primary Thyroid-like Follicular Renal Cell Carcinoma is a possible treatment option. Here the blood supply to the tumor is blocked resulting in tumor death
• Newer therapies, such as immunotherapy and targeted drug therapy, are being developed against kidney cancer. The healthcare provider will recommend the best treatment option based on their assessment of the affected individual

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.

How can Primary Thyroid-like Follicular Renal Cell Carcinoma be Prevented?

Current medical research has not established a method of preventing Primary Thyroid-like Follicular Renal Cell Carcinoma.

• Regular health check-ups might help those individuals with a history of the condition in the immediate family and help diagnose kidney cancers 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 Primary Thyroid-like Follicular Renal Cell Carcinoma include reducing the contributory risk factors for kidney cancer such as:

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

What is the Prognosis of Primary Thyroid-like Follicular Renal Cell Carcinoma? (Outcomes/Resolutions)

The prognosis of Primary Thyroid-like Follicular Renal Cell Carcinoma depends on the size of the tumor, their localization, and spread. In many cases, the prognosis is good with adequate treatment (surgical removal of the tumor).

• In general, 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
  • Size of tumors: Tumors that are smaller have better prognosis than tumors that are large at the time of diagnosis
  • 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 the tumor 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 lymph nodes or lungs, the possibility of prolonged survival following diagnosis is generally 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 Thyroid-like Follicular Renal Cell Carcinoma:

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

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