The most common primary tumor of the heart is the myxoma. In surgical series, the myxoma makes up as much as 77% of all primary tumors of the heart. Less common tumors of the heart include lipoma and cystic tumor of the atrioventricular nodal region.

Primary tumors of the heart are extremely rare tumors that arise from the normal tissues that make up the heart. This is in contrast to secondary tumors of the heart, which are typically either metastatic from another part of the body, or infiltrate the heart via direct extension from the surrounding tissues.

A papillary fibroelastoma is generally considered pathologically benign, however outflow obstruction or embolism can be associated with syncope, chest pain, heart attack, stroke and sudden cardiac death.

Symptoms due to papillary fibroelastomas are generally due to either mechanical effects of the tumor or due to embolization of a portion of the tumor to a distal organ. In particular, chest pain or syncope may be due to transient occlusion of the left main coronary artery by the tumor, while a heart attack or sudden cardiac death may be due to embolization of a portion of the tumor into a coronary artery.

A papillary fibroelastoma is a primary tumor of the heart that typically involves one of the valves of the heart. Papillary fibroelastomas, while considered generally rare, make up about 10 percent of all primary tumors of the heart. They are the third most common type of primary tumor of the heart, behind cardiac myxomas and cardiac lipomas.

Cardiac fibroma is a slow-growing tumor that can cause heart electrical transmission defects and arrhythmias. Some features may be seen in the ventricle wall separating the right and left lower chambers or the ventricle muscle. This tumor is rarely seen in atrial locations. Cardiac fibromas are mostly single and well-circumscribed and the average size of the tumor is circular and is 5 cm. Sometimes signs and symptoms are difficult to find in 35% of individuals. Situations like this, the tumor is incidentally diagnosed during a health checkup for other medical conditions. An individual may have abnormal heart sounds, such as a heart murmur.

In 65% of individuals, signs and symptoms are more obvious due to the large size of the tumor. Also, there is blood flow obstruction, especially into or out of the valves. The valves function becomes affected, which leads to heart failure. An individual might experience bluish skin (cyanosis), severe arrhythmias, dizziness, fainting, and other obstructive symptoms may be present.

Symptoms associated with cardiac myxomas are typically due to the effect of the mass of the tumor obstructing the normal flow of blood within the chambers of the heart. Because pedunculated myxomas are somewhat mobile, symptoms may only occur when the patient is in a particular position.

Some symptoms of myxoma may be associated with the release of interleukin 6 (IL-6) by the myxoma. High levels of IL-6 may be associated with a higher risk of embolism of the myxoma.

Symptoms of a cardiac myxoma include:

- Dyspnea on exertion

- Paroxysmal nocturnal dyspnea

- Fever

- Weight loss (see cachexia)

- Lightheadedness or syncope (Loss of consciousness)

- Hemoptysis

- Sudden death

- Tachycardia or milder heartrate, i.e. 75 - 100 cycl/min

Cardiac fibroma, also known as cardiac fibromatosis, is a rare benign tumor of the heart that occurs primarily in infants and children. Benign tumors are typically a solitary, firm grey-white, non-encapsulated tumor that is composed of fibrous and dense connective tissue. It is most commonly located in the interventricular septum or left ventricular wall. Symptoms depend on the size of the tumor, its location relative to the conduction system, and whether it obstructs blood flow. Two-thirds of children with this tumor are asymptomatic, showing no signs and symptoms. Symptomatic cardiac fibromas may be treated by surgical resection. It is associated with Gorlin syndrome. Benign cardiac tumors are rare, 75% are histologically benign. Cardiac fibromas only occur 4-6%, which is less common compared to myxomas (75%) and rhabdomymoas (5-10%).

The diagnosis of these tumors require physical checkups, imaging studies on the heart, and specialized tests to evaluate the heart. Cardiac fibroma is considered a congenital tumor where an ultrasound prenatal scan may help detect during fetal stage. Surgery is the best treatment for an individual with cardiac fibroma. During this surgery, the tumor is completely removed by the surgeon. The overall prognosis is very good with a surgical removal. There have been 200 cases of cardiac fibroma recorded in the medical literature. Risk factors are still unidentified, but 1 in 30 individuals with Gorlin syndrome are known to be present with cardiac fibroma.

Dilated cardiomyopathy develops insidiously, and may not initially cause symptoms significant enough to impact on quality of life. Nevertheless, many people experience significant symptoms. These might include:

- Shortness of breath

- Syncope (fainting)

- Angina, but only in the presence of ischemic heart disease

A person suffering from dilated cardiomyopathy may have an enlarged heart, with pulmonary edema and an elevated jugular venous pressure and a low pulse pressure. Signs of mitral and tricuspid regurgitation may be present.

1.SMA, smooth muscle actin. 2.MSA, muscle-specific actin. 3.EMA, epithelial membrane antigen.

Untreated hearts with RCM often develop the following characteristics:

- M or W configuration in an invasive hemodynamic pressure tracing of the RA

- Square root sign of part of the invasive hemodynamic pressure tracing Of The LV

- Biatrial enlargement

- Thickened LV walls (with normal chamber size)

- Thickened RV free wall (with normal chamber size)

- Elevated right atrial pressure (>12mmHg),

- Moderate pulmonary hypertension,

- Normal systolic function,

- Poor diastolic function, typically Grade III - IV Diastolic heart failure.

Those afflicted with RCM will experience decreased exercise tolerance, fatigue, jugular venous distention, peripheral edema, and ascites. Arrhythmias and conduction blocks are common.

Up to 80% of individuals with ARVD present have symptoms like syncope and dyspnea.The remainder frequently present with palpitations or other symptoms due to right ventricular outflow tract (RVOT) tachycardia (a type of monomorphic ventricular tachycardia).

Symptoms are usually exercise-related. In populations where hypertrophic cardiomyopathy is screened out prior to involvement in competitive athletics, it is a common cause of sudden cardiac death.

The first clinical signs of ARVD are usually during adolescence. However, signs of ARVD have been demonstrated in infants.

The clinical course of HCM is variable. Many people with HCM are asymptomatic or mildly symptomatic, and many of those carrying disease genes for HCM do not have clinically detectable disease. The symptoms and signs of HCM include shortness of breath due to stiffening and decreased blood filling of the ventricles, exertional chest pain (sometimes known as angina) due to reduced blood flow to the coronary arteries, uncomfortable awareness of the heart beat (palpitations), as well as disruption of the electrical system running through the abnormal heart muscle, lightheadedness, weakness, fainting and sudden cardiac death.

Dyspnea is largely due to increased stiffness of the left ventricle (LV), which impairs filling of the ventricles, but also leads to elevated pressure in the left ventricle and left atrium, causing back pressure and interstitial congestion in the lungs. Symptoms are not closely related to the presence or severity of an outflow tract gradient. Often, symptoms mimic those of congestive heart failure (esp. activity intolerance and dyspnea), but treatment of each is different. Beta blockers are used in both cases, but treatment with diuretics, a mainstay of CHF treatment, will exacerbate symptoms in hypertrophic obstructive cardiomyopathy by decreasing ventricular preload volume and thereby increasing outflow resistance (less blood to push aside the thickened obstructing tissue).

Major risk factors for sudden death in individuals with HCM include prior history of cardiac arrest or ventricular fibrillation, spontaneous sustained ventricular tachycardia, family history of premature sudden death, unexplained syncope, LV thickness greater than or equal to 30 mm, abnormal exercise blood pressure and nonsustained ventricular tachycardia.

Abdominal organs, including the liver, stomach, intestinal tract, and spleen may be randomly arranged throughout the left-right axis of the body. Distribution of these organs largely dictates treatment, clinical outcomes, and further evaluation.

The liver is typically symmetrical across the left-right axis in patients with situs ambiguous, which is abnormal. A majority of left atrial isomeric patients have defects throughout the biliary tree, which is responsible for bile production, even when the gall bladder is functional and morphologically normal. This biliary atresia can lead to acute problems such as nutrient malabsorption, pale stools, dark urine, and abdominal swelling. If this condition continues without proper treatment, cirrhosis and liver failure become a major concern. Biliary atresia is not usually observed in patients with right atrial isomerism.

Random positioning of the stomach is often one of the first signals of situs ambiguous upon examination. Malrotation of the entire intestinal tract, or improper folding and bulging of the stomach and intestines, results in bowel obstruction. This impairment leads to vomiting, abdominal distention, mucus and blood in the stool. Patients may also experience abdominal pain. Intestinal malrotation is more commonly identified in patients with right atrial isomerism than in those with left atrial isomerism.

Isomeric patients often experience disruptions to splenic development during embryogenesis, resulting in an overall lack a spleen (asplenia) or development of many spleens (polysplenia). Asplenia is most often observed in patients with right atrial isomerism. Polysplenia results in 90% of patients with left atrial isomerism. Although they have many spleens, each is usually ineffective resulting in functional asplenia. Rarely, left atrial isomeric patients have a single, normal, functional spleen. Patients lacking a functional spleen are in danger of sepsis and must be monitored.

Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited heart disease.

ARVD is caused by genetic defects of the parts of heart muscle (also called "myocardium" or "cardiac muscle") known as desmosomes, areas on the surface of heart muscle cells which link the cells together. The desmosomes are composed of several proteins, and many of those proteins can have harmful mutations.

The disease is a type of nonischemic cardiomyopathy that involves primarily the right ventricle. It is characterized by hypokinetic areas involving the free wall of the right ventricle, with fibrofatty replacement of the right ventricular myocardium, with associated arrhythmias originating in the right ventricle.

ARVD can be found in association with diffuse palmoplantar keratoderma, and woolly hair, in an autosomal recessive condition called Naxos disease, because this genetic abnormality can also affect the integrity of the superficial layers of the skin most exposed to pressure stress.

ARVC/D is an important cause of ventricular arrhythmias in children and young adults. It is seen predominantly in males, and 30–50% of cases have a familial distribution.

Isomerism of the bronchial tree is not typically damaging and presents no significant clinical complications. Pulmonary valve stenosis results in issues of blood flow to the lungs.

Restrictive cardiomyopathy (RCM) is a form of cardiomyopathy in which the walls of the heart are rigid (but not thickened). Thus the heart is restricted from stretching and filling with blood properly. It is the least common of the three original subtypes of cardiomyopathy: hypertrophic, dilated, and restrictive.

It should not be confused with constrictive pericarditis, a disease which presents similarly but is very different in treatment and prognosis.

Boxer cardiomyopathy is an adult-onset disease with three distinct clinical presentations:

The concealed form is characterized by an asymptomatic dog with premature ventricular contractions (PVCs).

The overt form is characterized by ventricular tachyarrhythmias and syncope. Dogs with overt disease may also have episodic weakness and exercise intolerance, but syncope is the predominant manifestation.

The third form, which is recognized much less frequently, is characterized by myocardial systolic dysfunction. This may result in left-sided, right-sided, or bi-ventricular congestive heart failure. It is not known if this form represents a separate clinical entity, or whether it is part of the continuum of disease.

While most carcinoids are asymptomatic through the natural lifetime and are discovered only upon surgery for unrelated reasons (so-called "coincidental carcinoids"), all carcinoids are considered to have malignant potential.

About 10% of carcinoids secrete excessive levels of a range of hormones, most notably serotonin (5-HT), causing:

- Flushing (serotonin itself does not cause flushing). Potential causes of flushing in carcinoid syndrome include bradykinins, prostaglandins, tachykinins, substance P, and/or histamine, diarrhea, and heart problems. Because of serotonin's growth-promoting effect on cardiac myocytes,[14] a serotonin-secreting carcinoid tumour may cause a tricuspid valve disease syndrome, due to the proliferation of myocytes onto the valve.

- Diarrhea

- Wheezing

- Abdominal cramping

- Peripheral edema

The outflow of serotonin can cause a depletion of tryptophan leading to niacin deficiency. Niacin deficiency, also known as pellagra, is associated with dermatitis, dementia, and diarrhea.

This constellation of symptoms is called "carcinoid syndrome" or (if acute) "carcinoid crisis". Occasionally, haemorrhage or the effects of tumor bulk are the presenting symptoms. The most common originating sites of carcinoid is the small bowel, particularly the ileum; carcinoid tumors are the most common malignancy of the appendix. Carcinoid tumors may rarely arise from the ovary or thymus.

They are most commonly found in the midgut at the level of the ileum or in the appendix. The next most common affected area is the respiratory tract, with 28% of all cases — per PAN-SEER data (1973 – 1999). The rectum is also a common site.

Symptoms of cardiomyopathies may include fatigue, swelling of the lower extremities and shortness of breath. Further indications of the condtion may include:

- Arrhythmia

- Fainting

- Diziness

Cardiomyopathies can be classified using different criteria:

- Primary/intrinsic cardiomyopathies

- Genetic

- Hypertrophic cardiomyopathy

- Arrhythmogenic right ventricular cardiomyopathy (ARVC)

- LV non-compaction

- Ion Channelopathies

- Dilated cardiomyopathy (DCM)

- Restrictive cardiomyopathy (RCM)

- Acquired

- Stress cardiomyopathy

- Myocarditis

- Ischemic cardiomyopathy

- Secondary/extrinsic cardiomyopathies

- Metabolic/storage

- Fabry's disease

- hemochromatosis

- Endomyocardial

- Endomyocardial fibrosis

- Hypereosinophilic syndrome

- Endocrine

- diabetes mellitus

- hyperthyroidism

- acromegaly

- Cardiofacial

- Noonan syndrome

- Neuromuscular

- muscular dystrophy

- Friedreich's ataxia

- Other

- Obesity-associated cardiomyopathy

The most common cancers in children are (childhood) leukemia (32%), brain tumors (18%), and lymphomas (11%). In 2005, 4.1 of every 100,000 young people under 20 years of age in the U.S. were diagnosed with leukemia, and 0.8 per 100,000 died from it. The number of new cases was highest among the 1–4 age group, but the number of deaths was highest among the 10–14 age group.

In 2005, 2.9 of every 100,000 people 0–19 years of age were found to have cancer of the brain or central nervous system, and 0.7 per 100,000 died from it. These cancers were found most often in children between 1 and 4 years of age, but the most deaths occurred among those aged 5–9. The main subtypes of brain and central nervous system tumors in children are: astrocytoma, brain stem glioma, craniopharyngioma, desmoplastic infantile ganglioglioma, ependymoma, high-grade glioma, medulloblastoma and atypical teratoid rhabdoid tumor.

Other, less common childhood cancer types are:

- Neuroblastoma (6%, nervous system)

- Wilms tumor (5%, kidney)

- Non-Hodgkin lymphoma (4%, blood)

- Childhood rhabdomyosarcoma (3%, many sites)

- Retinoblastoma (3%, eye)

- Osteosarcoma (3%, bone cancer)

- Ewing sarcoma (1%, many sites)

- Germ cell tumors (5%, many sites)

- Pleuropulmonary blastoma (lung or pleural cavity)

- Hepatoblastoma and hepatocellular carcinoma (liver cancer)

Pulmonary neuroendocrine tumors are neuroendocrine tumors localized to the lung: bronchus or pulmonary parenchyma.

Pulmonary neuroendocrine tumors include a spectrum of tumors from the low-grade typical pulmonary carcinoid tumor and intermediate-grade atypical pulmonary carcinoid tumor to the high-grade pulmonary large cell neuroendocrine carcinoma (LCNEC) and pulmonary small cell carcinoma (SCLC), with significant clinical, epidemiologic and genetic differences.

Boxer cardiomyopathy (also known as "Boxer arrhythmogenic right ventricular cardiomyopathy") is a disease of the myocardium primarily affecting Boxer dogs. It is characterized by the development of ventricular tachyarrhythmias, resulting in syncope and sudden cardiac death. Myocardial failure and congestive heart failure are uncommon manifestations of the disease.

Carcinoid (also carcinoid tumor) is a slow-growing type of neuroendocrine tumor originating in the cells of the neuroendocrine system. In some cases, metastasis may occur. Carcinoid tumors of the midgut (jejunum, ileum, appendix, and cecum) are associated with carcinoid syndrome.

Carcinoid tumors are the most common malignant tumor of the appendix, but they are most commonly associated with the small intestine, and they can also be found in the rectum and stomach. They are known to grow in the liver, but this finding is usually a manifestation of metastatic disease from a primary carcinoid occurring elsewhere in the body. They have a very slow growth rate compared to most malignant tumors. The median age at diagnosis for all patients with neuroendocrine tumors is 63 years.

Upon cardiac catheterization, catheters can be placed in the left ventricle and the ascending aorta, to measure the pressure difference between these structures. In normal individuals, during ventricular systole, the pressure in the ascending aorta and the left ventricle will equalize, and the aortic valve is open. In individuals with aortic stenosis or with HCM with an outflow tract gradient, there will be a pressure gradient (difference) between the left ventricle and the aorta, with the left ventricular pressure higher than the aortic pressure. This gradient represents the degree of obstruction that has to be overcome in order to eject blood from the left ventricle.

The Brockenbrough–Braunwald–Morrow sign is observed in individuals with HCM with outflow tract gradient. This sign can be used to differentiate HCM from aortic stenosis. In individuals with aortic stenosis, after a premature ventricular contraction (PVC), the following ventricular contraction will be more forceful, and the pressure generated in the left ventricle will be higher. Because of the fixed obstruction that the stenotic aortic valve represents, the post-PVC ascending aortic pressure will increase as well. In individuals with HCM, however, the degree of obstruction will increase more than the force of contraction will increase in the post-PVC beat. The result of this is that the left ventricular pressure increases and the ascending aortic pressure "decreases", with an increase in the LVOT gradient.

While the Brockenbrough–Braunwald–Morrow sign is most dramatically demonstrated using simultaneous intra-cardiac and intra-aortic catheters, it can be seen on routine physical examination as a decrease in the pulse pressure in the post-PVC beat in individuals with HCM.