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

• Low-Grade Neuroendocrine Tumor of Kidney
• Renal Carcinoid Tumor
• Well-Differentiated Neuroendocrine Tumor of Kidney

What is Carcinoid Tumor of Kidney? (Definition/Background Information)

• Carcinoid Tumor of Kidney is a type of neuroendocrine carcinoma. The malignant tumor generally affects adult males and females. The exact cause of development of the tumor is presently unknown, but it may be due to genetic factors
• The risk factors for developing Carcinoid Tumor of Kidney 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 Carcinoid Tumor of Kidney include blood in urine, a lump on the side of the abdomen, flank pain, unexplained fever, and unexplained weight loss. The tumors can be slow-growing, and some may secrete hormones causing paraneoplastic syndrome
• It may give rise to complications such as spread of cancer to other parts of the body. The healthcare provider might diagnose Carcinoid Tumor of Kidney using blood tests, imaging studies, and tissue biopsy, as necessary. Genetic testing may be required in some cases
• The treatment options include surgery, radiation therapy, chemotherapy, and targeted drug therapy. The prognosis of Carcinoid Tumor of Kidney 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)
• 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 Carcinoid Tumor of Kidney? (Age and Sex Distribution)

• Carcinoid Tumor of Kidney generally affects adult men and women. However, it may be seen in a wider age range of individuals
• The cancer is not specific to any ethnic or racial group

What are the Risk Factors for Carcinoid Tumor of Kidney? (Predisposing Factors)

In a majority of individuals, no clear-cut risk factors for Carcinoid Tumor of Kidney have been established to date.  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 Carcinoid Tumor of Kidney? (Etiology)

Currently, scientists do not know the definitive factor(s) causing Carcinoid Tumor of Kidney.

• Studies have shown some genetic mutations in this carcinoid tumor
• Some of these mutations include: Loss of heterozygosity on locus chromosome 3p21

Research is underway to well-characterize these mutations.

What are the Signs and Symptoms of Carcinoid Tumor of Kidney?

Carcinoid Tumor of Kidney does not cause significant signs and symptoms in many individuals. In others, the signs and symptoms associated with this carcinoid tumor 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
• A visible lump may be seen on the side of the abdomen. The tumors can be large, ranging up to 17 cm in size
• Fluid accumulation in the lower legs (pedal edema)
• Flank pain
• Unexplained weight loss
• Flushing, dyspnea, diarrhea due to hormone secretion (paraneoplastic syndrome)
  • If the tumors secrete adrenocorticotropic hormone (ACTH), then it can cause Cushing’s syndrome
  • If the tumors secrete vasoactive intestinal peptide (VIP), then it can cause watery diarrhea, hypokalemia, and achlorhydria
  • If the tumors secrete serotonin, then it can cause diarrhea, headache, increased body temperature and sweating, tremors, and flushing
• Night sweats, unexplained fever
• Generalized weakness and pain in the body
• Abnormal liver function test
• If the tumor is associated with carcinoid/paraneoplastic syndrome (which may be seen in less than 10% of the cases); then, the following may be noted:
  • Increased blood pressure (hypertension)
  • Increased calcium in blood (hypercalcemia)
  • Increased red blood cells (erythrocytosis)
  • Increased platelets (thrombocytosis)

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

How is Carcinoid Tumor of Kidney Diagnosed?

Many of the Carcinoid Tumor of Kidney are diagnosed incidentally during imaging studies for some other condition. A healthcare provider might employ one or several of the following tools to diagnose the tumor:

• 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)
• Urine analysis such as albumin levels
• Blood tests for ACTH levels, VIP levels, serum chromogranin and serum serotonin
• 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)
• Octreotide scintigraphy can help detect functional neuroendocrine tumor, and in some cases, liver metastasis. Functional neuroendocrine tumors are tumors that secrete hormones, such as ACTH, VIP, and serotonin, causing signs and symptoms such as the following:
  • ACTH causes Cushing’s syndrome
  • VIP causes watery diarrhea, low potassium levels (hypokalemia), and low production of gastric acid in stomach (achlorhydria)
  • Serotonin causes headaches, flushing, and diarrhea

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

Note: On radiological imaging studies, the tumor may show calcification.

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 Carcinoid Tumor of Kidney?

The possible complications associated with Carcinoid Tumor of Kidney include:

• Metastasis: The cancer can spread to other areas of the body, such as to the liver, lung, and lymph nodes
• Complications due to surgery
• Side effects of chemotherapy (such as toxicity) and radiation therapy

How is Carcinoid Tumor of Kidney Treated?

The treatment measures Carcinoid Tumor 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 (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 Carcinoid Tumor of Kidney) 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 Carcinoid Tumor 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 (recurrent Carcinoid Tumor of Kidney)
  • Tumors that have spread to distant parts of the body (metastatic Carcinoid Tumor of Kidney)
• Immunotherapy for Carcinoid Tumor of Kidney: A patient’s immune system is activated to combat the cancer in this form of therapy
• Targeted drug therapy for Carcinoid Tumor of Kidney: This form of drug treatment targets and kills cancer cells specifically, while not harming the surrounding normal/healthy cells
• Arterial embolization of Carcinoid Tumor of Kidney is a possible treatment option. Here the blood supply to the tumor is blocked resulting in tumor death

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 Carcinoid Tumor of Kidney be Prevented?

Current medical research has not established a method of preventing Carcinoid Tumor of Kidney.

• 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 Carcinoid Tumor of Kidney include reducing the contributory risk factors, such as:

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

What is the Prognosis of Carcinoid Tumor of Kidney? (Outcomes/Resolutions)

The prognosis of Carcinoid Tumor of Kidney depends on the size and number of tumors, their localization, and spread. In many cases, the prognosis is excellent. The tumors are usually slow-growing and diagnosed at an early stage.

• The most reliable prognostic factor of Carcinoid Tumor of Kidney is dependent on whether the tumor can be completely removed through surgery with free margins or not (no traces of the tumor in adjoining tissue)
• 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 less than 4 cm have better prognosis than tumor greater than 4 cm
  • 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
  • Tumors that have solid pattern when examined under microscope have worse prognosis
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals. In general, individuals greater than 40 years have worse prognosis
  • Tumors that have high mitotic activity (greater than one mitosis per high power field) have worse prognosis
  • 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 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 Carcinoid Tumor of Kidney:

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

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