Intestinal neoplasia is a rare condition in horses associated with abnormal cellular replication (i.e. tumors), which is then classified as either benign, malignant or malignant-metastatic in nature. Lymphoma and adenocarcinoma are the two neoplasia types diagnosed most commonly, however many cell types in the intestinal tract can become neoplastic, including smooth muscle cells, nerve cells and epithelial cells.
Some intestinal neoplasias only grow locally, while others can disseminate throughout the intestine, or metastasize aggressively throughout the body. All segments of the alimentary system can be affected, however the small intestine is most commonly involved.
The clinical signs of intestinal neoplasia tend to be nonspecific and can include weight loss, colic, inappetence and fever. Many diseases present with similar clinical signs, such as inflammatory bowel disease, intestinal ulceration, helminthosis, kidney and liver disease, and other types of neoplasia that arise from outside of the intestinal tract.
The long-term prognosis for horses with intestinal neoplasia is generally very poor. Surgical removal of focally growing tumours might be curative. The field of equine oncology is developing and treatment options such as chemotherapy are becoming more available, however at this stage, limited information is available on the success rates of treatments for intestinal neoplasia in horses.
It’s important to note that thatnot many large scale research studiescurrently existon intestinal neoplasia, only small studies, and sometimes the information reported is different. The findings referenced in this article represent statements most researchers were making in the existing literature.
Pathophysiology & Presentationof Intestinal Neoplasia in Horses
The most common forms of intestinal neoplasia include lymphoma, adenocarcinoma and squamous cell carcinoma. Less common forms are neoplastic smooth muscle (leiomyomas and leiomyosarcomas), neurofibromas, and metastatic neoplasia that initially form outside the intestinal tract. Common clinical signs of intestinal neoplasia include weight loss, colic, anorexia and fever (Taylor, 2006).
Table 1. A summary of most likely intestinal neoplasia types to be found in different anatomical locations.
|ANATOMICAL LOCATION||NEOPLASIA TYPE||FOCAL/DISSEMINATED||TREATMENT/PROGNOSIS|
|Esophagous||SCC, leiomyosarcoma||Focal||Grave prognosis|
|Focal, can metastasize|
Adenocarcinoma, leiomyosarcoma, neurofibroma
|Chemotherapy might be possible, poor prognosis.|
Surgical removal might be possible
Surgical resolution might be possible
Surgical removal might be possible
Squamous Cell Carcinomas
Squamous cell carcinomas (SCC) have been reported to occur in the esophagus and stomach. Up to 80% of stomach tumors are reported to be SCCs. SCCs can metastasize into the abdominal cavity and the surrounding viscera. There is no breed, or sex predilection for SCCs, but they tend to occur in older horses. SCCs of the stomach and esophagus can present in a variety of ways including choke, gastric reflux, colic and weight loss.
Lymphosarcoma/Lymphoma of the intestinal tract may occur as either the alimentary form or the multicentric form. Veterinary pathologists prefer the term Lymphoma to Lymphosarcoma, as there is no benign form of this disease in horses.
Alimentary lymphoma is the most common form of intestinal neoplasia and tends to affect middle aged horses, with a mean age of 16 years (Taylor et al., 2006). The Standardbred breed may be more at risk (Durham et al., 2013). Alimentary lymphoma arises most commonly from the small intestine and tends to spread diffusely, metastasizing to the intestinal and visceral lymph nodes and may spread to the liver, spleen and kidney. Peripheral lymphadenopathy usually does not occur. Alimentary lymphoma causes weight loss, mild recurrent colic, and/or recurrent episodes of fever. Diarrhea is uncommon, but the fecal consistency may be altered.
Multicentric lymphoma affects older horses, with a mean age of 20 years (Taylor et al., 2006). Multicentric lymphoma presents as a more severe form of disease as it affects more organ systems, with clinical signs such as peripheral lymphadenopathy, emaciation and ventral edema a feature of the disease.
Lymphomas can be further classified by immunophenotyping, which can help equine oncologists develop treatment regimes, and assist in prediction of the response to treatment and the prognosis.
The immunophenotypes reported to occur most commonly with alimentary lymphoma include: T-cell-rich Large B cell lymphoma, Peripheral T cell lymphoma and Enteric-associated T cell lymphoma. The first 2 immunophenotypes are also common forms seen with multicentric lymphoma (Durham et al., 2013).
Adenocarcinomas are malignant tumors that arise from the glandular cells that line the intestinal tract. This tumor type can affect the stomach, small intestine, large intestine and cecum – the latter two sites are most commonly affected. These tumors tend to grow locally, but also can metastasize aggressively, and by the time they are diagnosed, tumor proliferation is often extensive (Völker et al., 2017). Metastatic disease to the bone marrow has been reported. Adenocarcinomas are diagnosed in middle aged to older horses, and present with nonspecific clinical signs such as recurrent colic and weight loss. The Arabian breed may be predisposed to this type of neoplasia (Taylor et al., 2006).
Leiomyosarcomas and Leiomyomas
Leiomyosarcomas and Leiomyomas are rare smooth muscle tumors (malignant and benign respectively) that can occur throughout the intestinal tract, from the oesophagus to the small colon. They are focally growing tumors that are usually only diagnosed once they cause obstruction of the intestinal lumen, resulting in symptoms of colic or choke. Leiomyosarcoma can metastasize (Taylor et al., 2006).
Neurofibromas are a nerve-sheath tumour that occur rarely, and are a focally growing tumor that usually only cause symptoms once they are obstructing the intestinal lumen.
Metastatic disease of origin outside the intestinal tract can also affect the alimentary system – some possibilities include bile duct carcinomas and mesothelioma.
Lipomas are a benign form of fatty tumor that occur in older horses. Lipomas grow from adipocytes in the intestinal mesentery, and as they grow in size, the increasing weight of the tumor pulls at the mesentery, creating a pedunculated attachment. This free-swinging tumor can then become entangled in the motile small intestine or the less motile small colon and rectum. In its most severe form, the pedunculated lipoma can strangulate intestinal loops (particularly in the small intestine), resulting in sudden onset severe colic symptoms that require emergency treatment. Older, overweight Quarterhorse broodmares have been reported to be more prone to this disease, as are older geldings and ponies (Smith, 2015; Reed, 2010).
Paraneoplastic syndromes occur rarely as a consequence of intestinal neoplasia, and are caused either by the release of hormones or cytokines from the neoplastic cells, or by activation of the host immune system. Reported paraneoplastic syndromes have included:
- Pruritis and alopecia
- Hypertrophic osteopathy
- Immune-mediated haemolytic anemia
Diagnosing Intestinal Neoplasia in Horses
The clinical signs for intestinal neoplasia will depend on the location of the lesion, and the size and metastasizing nature of the disease. The diagnostic work-up will therefore need to be adapted for the individual case.
Neoplasia of the esophagus or stomach can present with symptoms of gastric reflux or choke, and there may be difficulty passing a nasogastric tube. Endoscopy or barium contrast radiography may be most useful to visualize the lesion. Biopsy of the lesion in these locations can be challenging.
Neoplasia of the small and large intestine requires a full work-up to first rule out more common causes of weight loss, colic and fever.
- Anemia is common, especially with lymphoma and adenocarcinoma, and may be attributed either to chronic inflammation, immune-mediated hemolytic anemia, or blood loss into the intestinal lumen.
- The leukogram is often inflammatory (lymphocytosis and/or neutrophilia), but in rare instances, may be leukemic due to infiltration of neoplastic cells into the bone marrow.
- Hypoalbuminemia is a common finding, due to malabsorption or leakage from intestinal damage.
- Hypocalcaemia is usually seen concurrent to the hypoalbuminemia. Hypercalcaemia, as a paraneoplastic syndrome, is rare.
- Hyperfibrinogenaemia is reported as a frequent feature of adenocarcinoma, and may be seen with other neoplastic types.
- Liver enzymes might be elevated with metastatic disease, or secondary to intestinal stasis. Azotemia might be found in dehydrated horses, or if metastatic disease affects the kidney.
Rectal palpation can help identify abdominal masses, or distended loops of bowel.
Peritoneal fluid is usually diagnosed as a transudate or modified transudate, unless intestinal damage is severe, then hemorrhage or peritonitis might be present. The peritoneal fluid can occasionally yield neoplastic cells. Lymphoma, SCC and adenocarcinoma have been diagnosed from peritoneal fluid, with lymphoma being most commonly identified. Researchers have found that between 21-50% of cases of alimentary lymphoma are positive for neoplastic cells in the peritoneal fluid.
Abdominal and transrectal ultrasound can be used to identify:
- Intestinal wall that is thickened or has abnormal echogenicity,
- Intestinal masses,
- Abdominal lymphadenopathy,
- Peritoneal effusion
- Splenic and hepatic masses (Janvier et al., 2016).
Transrectal ultrasound is particularly useful for examining the lumboaortic lymph nodes.
An Oral Glucose Absorption Test may be positive in cases where the neoplasia is affecting a large portion of intestine, causing malabsorptive disease.
A fecal occult blood test might be positive. Taylor et al. (2016) found that adenocarcinoma was most likely to yield a positive fecal occult blood test, and that these horses also were anemic, suggesting significant bleeding into the intestinal lumen.
Rectal biopsy frequently appears inflammatory in cases of intestinal neoplasia. Rectal biopsy is also occasionally diagnostic, particularly in cases of alimentary lymphoma (Taylor et al., 2006)
Exploratory laparotomy and biopsy of the affected intestine is often required for a definitive diagnosis. Laparoscopic biopsy may be available in specialist centers.
Immunophenotyping of the biopsy sample can be useful to classify lymphoma types.
Treatmentof Intestinal Neoplasia in Horses
Focally growing, non-metastasizing tumors that affect a small area of intestine may be resolved with surgical resection. Strangulating lipomas can also be fixed surgically. In both cases, resection of bowel and anastomosis is highly likely to be needed.
Lymphoma has the potential to be treatable with chemotherapy. It is worth contacting a specialist equine hospital to find out what chemotherapy regimes are possible, as this is an evolving field of research. Alimentary lymphoma may also respond in the short term to corticosteroid treatment.
There is no known instigating cause for intestinal tumors yet – no specific bacterial or viral agent has been identified, against which a vaccination or such could be produced.
Durham, A.C. et al. (2013) Two Hundred Three Cases of Equine Lymphoma Classified According to the World Health Organisation (WHO) Classification Criteria. Vet Pathol, 1:86-93.
Janvier, V. et al. (2016) Ultrasonographic findings in 13 horses with lymphoma. Vet Radiol Ultrasound, 57:65-74.
Reed, S.M. et al. (2010) Equine Internal Medicine, 3rd Ed. Saunders Elsevier, St Louis, pp. 894-5.
Smith, B. (2015) Diseases of the Alimentary System, in Large Animal Internal Medicine, chapter 32. Mosby, Missouri.
Taylor, S. et al. (2006) Intestinal neoplasia in horses. J Vet Intern Med, 20:1429-1436.
Völker, I. et al. (2017) Intestinal adenocarcinoma in ponies: Clinical and pathological findings. Equine Vet Educ, doi:10.1111/eve.12738.
Conclusions: Squamous cell carcinoma is the most common primary gastric neoplasia in horses.What is the digestive disorder that is fatal in horses? ›
Colitis-X. Colitis-X is a term used to describe undiagnosed causes of an extremely rapid, fatal intestinal inflammation of horses that causes a sudden onset of profuse, watery diarrhea and development of shock. Many affected horses have a history of stress.What is grumbling enteritis in horses? ›
Enteritis is a severe digestive problem in horses that can range from an acute condition requiring immediate care to a chronic disease that causes low-grade discomfort for months. No matter the specific cause of enteritis, accurate diagnosis and swift treatment is vital.Can horses get colon cancer? ›
Cancer can also appear as single or multiple masses that mechanically block the intestine, causing colic and obstruction. The most common infiltrative cancer in the horse is intestinal lymphosarcoma. The most common mass blocking the intestine is melanoma in gray horses.What are the two types of neoplasia? ›
Neoplasms may be benign (not cancer) or malignant (cancer). Benign neoplasms may grow large but do not spread into, or invade, nearby tissues or other parts of the body. Malignant neoplasms can spread into, or invade, nearby tissues. They can also spread to other parts of the body through the blood and lymph systems.How is gastric neoplasm diagnosed? ›
- Biopsy. ...
- Biomarker testing of the tumor. ...
- Endoscopy. ...
- Endoscopic ultrasound. ...
- X-ray. ...
- Barium swallow. ...
- Computed tomography (CT or CAT) scan. ...
- Magnetic resonance imaging (MRI).
- Colic, equine gastric ulcer syndrome (EGUS) and parasites are some of the most frequently seen diseases of horses' digestive systems. ...
- Foals are susceptible to developing gastric ulcers particularly if they are experiencing periods of stress such as hospitalisation or are placed in a stressful environment.
Abstract. Sudden gastrointestinal (GI) death is an unexpected death due to digestive system causes mainly found after autopsy. The literature is rich in articles that studied sudden death due to cardiac causes while sudden GI deaths remain less well-documented.What are the signs and symptoms of enteritis? ›
Symptoms may include:
- nausea and vomiting.
- loss of appetite.
- abdominal cramps and pain.
- pain, bleeding, or mucus-like discharge from the rectum.
Enteritis is inflammation of your small intestine. The most common causes are viral or bacterial infections and radiation exposure. Enteritis can also include the stomach (gastroenteritis) or the large intestine (enterocolitis). Enteritis caused by infection is often gastroenteritis.
Idiopathic Focal Eosinophilic Enteritis (IFEE) is a rare condition that causes colic in young horses. IFEE is characterized by a focal area of eosinophilic inflammation, in the small intestine, that results in narrowing of the intestinal lumen and obstruction of ingesta flow.What are 3 causes of colon cancer? ›
Lack of regular physical activity. A diet low in fruit and vegetables. A low-fiber and high-fat diet, or a diet high in processed meats. Overweight and obesity.What is equine neoplasia? ›
Intestinal neoplasia is a rare condition in horses associated with abnormal cellular replication (i.e. tumors), which is then classified as either benign, malignant or malignant-metastatic in nature.Which organ is colon cancer most likely to spread to? ›
Colon cancer most often spreads to the liver, but it can also spread to other places like the lungs, brain, peritoneum (the lining of the abdominal cavity), or to distant lymph nodes. In most cases surgery is unlikely to cure these cancers.What is the most common neoplasia? ›
The most common type of cancer on the list is breast cancer, with 290,560 new cases expected in the United States in 2022. The next most common cancers are prostate cancer and lung cancer.What is the treatment for neoplasia? ›
Treatment depends on the type and size of the tumor and whether it has spread to other areas of your body. If the malignant neoplasm is localized to one area, surgery may be an option. If the cancer has spread, then your healthcare provider may recommend chemotherapy, radiation therapy or targeted drug therapy.What are the stages of neoplasia? ›
Stage I means the cancer is small and only in one area. This is also called early-stage cancer. Stage II and III mean the cancer is larger and has grown into nearby tissues or lymph nodes. Stage IV means the cancer has spread to other parts of your body.What are the warning signs of neoplasm? ›
- Change in bowel or bladder habits.
- A sore that does not heal.
- Unusual bleeding or discharge.
- Thickening or lump in the breast or elsewhere.
- Indigestion or difficulty in swallowing.
- Obvious change in a wart or mole.
- Nagging cough or hoarseness.
Intestinal cancer, also called small intestine cancer or small bowel cancer, usually starts in the lining of the small intestine and may spread from the digestive system to other parts of the body. Most cases of intestinal cancer develop in the duodenum, or upper part of the small intestine.Can neoplasm be cured? ›
The sooner a malignant neoplasm is detected, the more effectively it can be treated, so early diagnosis is important. Many types of cancer can be cured. Treatment for other types can allow people to live for many years with cancer.
- Celiac disease – This is an autoimmune digestive disorder in which the body launches an immune reaction to gluten. ...
- Irritable Bowel Syndrome – IBS is a condition with abdominal pain or bloating associated with either diarrhea or constipation (or both).
Overview. Gastrointestinal (GI) symptoms such as heartburn, indigestion/dyspepsia, bloating and constipation are common in the community.What are 3 common disorders of the small intestine? ›
Intestinal cancer. Intestinal obstruction. Irritable bowel syndrome. Ulcers, such as peptic ulcer.What 2 diseases disorders conditions affect the digestive gastrointestinal system? ›
Common digestive disorders include gastroesophageal reflux disease, cancer, irritable bowel syndrome, lactose intolerance and hiatal hernia. The most common symptoms of digestive disorders include bleeding, bloating, constipation, diarrhea, heartburn, pain, nausea and vomiting.What are the six common digestive disorders? ›
- Gastroesophageal Reflux Disease (GERD) Heartburn happens, but if it occurs regularly, you may need to be evaluated for GERD. ...
- Chronic Diarrhea. ...
- Chronic Constipation. ...
- Gastroenteritis. ...
- Ulcers. ...
- Gastrointestinal Reflux Disease (GERD) Gastroesophageal reflux disease (GERD) occurs when stomach acid frequently flows back into your esophagus. ...
- Celiac Disease. ...
- Irritable Bowel Syndrome (IBS) ...
- Ulcerative Colitis. ...
- Crohn's Disease.
Bleeding is the most common cause of gastrointestinal tract smell.What are the first signs of internal bleeding? ›
- pain at the injured site.
- swollen, tight abdomen.
- nausea and vomiting.
- pale, clammy, sweaty skin.
- extreme thirst.
Gastrointestinal (GI) bleeding is a symptom of a disorder in your digestive tract. The blood often appears in stool or vomit but isn't always visible, though it may cause the stool to look black or tarry. The level of bleeding can range from mild to severe and can be life-threatening.What are 3 symptoms of intestinal infection? ›
- crampy abdominal pain.
Gastroenteritis is often mistaken for stomach flu although it is actually an inflammation of the lining of the intestines caused by a virus, bacteria or parasites. Symptoms of gastroenteritis include diarrhea, abdominal pain, vomiting, headache, fever and chills. Most people recover with no treatment.What are the four types of enteritis? ›
- Bacterial gastroenteritis.
- Campylobacter enteritis.
- E coli enteritis.
- Food poisoning.
- Radiation enteritis.
- Salmonella enteritis.
- Shigella enteritis.
- Staph aureus food poisoning.
Key points about gastroenteritis
Bacterial gastroenteritis is sometimes treated with antibiotics. If severe cases are not treated, they can lead to severe dehydration, neurological problems, kidney failure, and even death.
Co-trimoxazole and metronidazole are to be considered for oral administration. Azithromycin and rifaximin may also be used, based on local consideration or if signs of colitis are observed. Ceftriaxone, metronidazole, and ciprofloxacin may be considered in children with systemic and invasive diseases.What is intestinal catarrh? ›
Inflammation of mucous membranes accompanied by increased secretions - usually in the nose (as in the common cold) but can be applied to internal organs as well.(19thC)What autoimmune diseases cause eosinophilia? ›
- Acute myelogenous leukemia (AML)
- Ascariasis (a roundworm infection)
- Atopic dermatitis (eczema)
- Churg-Strauss syndrome.
- Crohn's disease.
This condition most often indicates a parasitic infection, an allergic reaction or cancer. You can have high levels of eosinophils in your blood (blood eosinophilia) or in tissues at the site of an infection or inflammation (tissue eosinophilia).What is the most common cause of eosinophilia? ›
Allergies are the most common cause of high eosinophil levels. You can prevent allergy-related eosinophilia with treatment to control your body's allergic reactions. But there are times when eosinophilia may be a sign of an underlying condition that you may not be able to prevent.What are the silent signs of colon cancer? ›
Colon cancer is considered a silent disease. Most of the time there are no symptoms. The symptoms that people may experience include a change in bowel habits, abdominal pain, blood in the stool, and weight loss. If individuals have these symptoms, the disease may already have advanced.What is the number one symptom of colon cancer? ›
The 3 main symptoms of bowel cancer are blood in the stools (faeces), changes in bowel habit – such as more frequent, looser stools – and abdominal (tummy) pain. However, these symptoms are very common and most people with them do not have bowel cancer.
- Benign: These tumors are not cancerous. They do not invade nearby tissue or spread to other parts of the body. ...
- Premalignant: In these tumors, the cells are not yet cancerous, but they can potentially become malignant.
- Malignant: Malignant tumors are cancerous.
The difference between a tumor and a neoplasm is that a tumor refers to swelling or a lump like swollen state that would normally be associated with inflammation, whereas a neoplasm refers to any new growth, lesion, or ulcer that is abnormal.Where does colon cancer usually metastasize first? ›
While colon cancer can travel throughout the body, there are specific areas where it is more likely to spread. The most common include the liver and lungs, as well as the brain, distant lymph nodes and peritoneum (membrane that lines the abdominal cavity).How fast does intestine cancer spread? ›
How fast does colon cancer spread? Colorectal cancer tends to spread to the liver and lungs 2 years after initial cancer surgery.Where does bowel cancer first appear? ›
Bowel cancer usually first develops inside clumps of cells called polyps on the inner lining of the bowel. However, it does not necessarily mean you'll get bowel cancer if you develop polyps. Some polyps go away by themselves, and some do not change.What is the most common benign tumor of the stomach? ›
The most common benign lesions in the stomach are polyps (epithelial tumors) and they constitute 75% of all benign stomach tumors. The other common benign stomach tumors are leiomyomas. In the duodenum, the most common benign lesion is adenoma including Brunner's gland adenomas, followed by leiomyomas and lipomas.What is the most common malignant tumor of the gastrointestinal tract? ›
“Colorectal cancers are the most common and most treatable GI cancers in the United States,” says Yale Medicine's Jeremy Kortmansky, MD, a medical oncologist. “About 5 to 10 percent occur from an inherited genetic risk factor, but the remaining cases happen sporadically.What is a neoplasm of the stomach? ›
Definition. A tumor (abnormal growth of tissue) of the stomach. [ from HPO]Are intestinal tumors always cancerous? ›
Tumors of the small intestine are rare. They are usually single, but may be multiple particularly in certain syndromes (i.e. intestinal polyposis syndrome). Tumors can be benign or malignant. Some benign tumors can progress and become malignant (i.e. adenomas, leiomyomas).What is the most common benign neoplasm of the small intestine? ›
Adenoma and gastrointestinal stromal tumor (GIST) are the most common benign small bowel tumors and the only two with malignant predisposition (35).
Most tumors of the small intestine are noncancerous (benign). These include tumors of fat cells (lipomas), nerve cells (neurofibromas), connective tissue cells (fibromas), and muscle cells (leiomyomas). Most noncancerous tumors of the small intestine do not cause symptoms.What tumor marker is found in gastrointestinal cancers? ›
Carcinoembryonic antigen (CEA) level: The tumor marker most often used in colorectal cancer. This level can be checked before surgery to predict prognosis, can be used during therapy to watch response to treatment, or when you are done treatment to watch for recurrence.Where do GI cancers metastasize? ›
Abstract. Primary gastrointestinal cancer frequently spreads to the mesentery, omentum and other parts of the peritoneum and these deposits are generally considered to be induced by intraperitoneal seeding from the primary lesion.What is the most common primary malignant tumor of the small intestine? ›
Adenocarcinoma. Adenocarcinoma is the most common primary malignancy of the SI and accounts for 40% of cancers (Table 1). The predominant location of adenocarcinoma is the duodenum and proximal jejunum, with the incidence decreasing distally .What is the treatment for neoplasm? ›
Chemotherapy. These drugs are administered to kill cancer cells and/or to stop their growth and spread. Radiation Therapy. Targeted beams of radiation can kill cancer cells.Can neoplastic disease be cured? ›
Chemotherapy can be used to either cure cancer or control the growth of the neoplasms. It is very effective in preventing the further spread of the disease and in slowing down the growth of malignant tumors.