Myxoma
Encyclopedia
A myxoma is a tumor
of primitive connective tissue
. It is the most common primary tumor of the heart
in adults, but can also occur in other locations.
The phrase "myxomatous degeneration
" refers to the process in which connective tissue
becomes filled with mucus.
or right atrium
of the heart; about 86 percent occur in the left atrium
.
Myxomas are typically pedunculated
, with a stalk that is attached to the interatrial septum
. The most common location for attachment of the stalk is the fossa ovalis
region of the interatrial septum.
, audible to auscultation
just after S2.
It is most seen on echocardiography
, as a pedunculated mass that is heterogeneous in appearance.
A left atrial myxoma will cause an increase in Pulmonary Capillary Wedge Pressure.
The differential diagnosis
include other cardiac tumors such as lipoma
s and rhabdomyoma
s (and rarely teratoma
s). These other tumors of the heart are typically not pedunculated, however, and are more likely to infiltrate
the muscle of the heart. Cardiac magnetic resonance imaging
(MRI) can help non-invasively diagnose cardiac tumors. However, diagnosis usually requires examination of a tissue sample
by a pathologist.
1.SMA, smooth muscle
actin
. 2.MSA, muscle-specific actin
. 3.EMA, epithelial membrane antigen
.
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:
.
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
of primitive connective tissue
Connective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
. It is the most common primary tumor of the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
in adults, but can also occur in other locations.
The phrase "myxomatous degeneration
Myxomatous degeneration
Myxomatous degeneration refers to a pathological weakening of connective tissue. The term is most often used in the context of mitral valve prolapse, which is known more technically as "primary form of myxomatous degeneration of the mitral valve."...
" refers to the process in which connective tissue
Connective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
becomes filled with mucus.
Location
Myxomas are usually located in either the leftLeft atrium
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle, via the mitral valve.-Foramen ovale:...
or right atrium
Right atrium
The right atrium is one of four chambers in the hearts of mammals and archosaurs...
of the heart; about 86 percent occur in the left atrium
Left atrium
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle, via the mitral valve.-Foramen ovale:...
.
Myxomas are typically pedunculated
Pedunculated
In medicine and zoology, a peduncle is a stalk-shaped mass of tissue. Pedunculated is a term that is used to describe a mass that has or is supported on a peduncle, such as a cyst or polyp.As opposed to sessile which lacks a stalk- References :*...
, with a stalk that is attached to the interatrial septum
Interatrial septum
The interatrial septum is the wall of tissue that separates the right and left atria of the heart.-Development:The interatrial septum forms during the first and second months of fetal development. Formation of the septum occurs in several stages...
. The most common location for attachment of the stalk is the fossa ovalis
Fossa ovalis
Fossa ovalis can refer to:* Fossa ovalis , also called the saphenous opening* Fossa ovalis , an embryonic remnant of the foramen ovale...
region of the interatrial septum.
Diagnosis
An atrial myxoma may create an extra heart soundHeart sounds
Heart sounds, or heartbeats, are the noises generated by the beating heart and the resultant flow of blood through it...
, audible to auscultation
Auscultation
Auscultation is the term for listening to the internal sounds of the body, usually using a stethoscope...
just after S2.
It is most seen on echocardiography
Echocardiography
An echocardiogram, often referred to in the medical community as a cardiac ECHO or simply an ECHO, is a sonogram of the heart . Also known as a cardiac ultrasound, it uses standard ultrasound techniques to image two-dimensional slices of the heart...
, as a pedunculated mass that is heterogeneous in appearance.
A left atrial myxoma will cause an increase in Pulmonary Capillary Wedge Pressure.
The differential diagnosis
Differential diagnosis
A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...
include other cardiac tumors such as lipoma
Lipoma
A lipoma is a benign tumor composed of adipose tissue. It is the most common form of soft tissue tumor. Lipomas are soft to the touch, usually movable, and are generally painless. Many lipomas are small but can enlarge to sizes greater than six centimeters. Lipomas are commonly found in adults...
s and rhabdomyoma
Rhabdomyoma
A rhabdomyoma is a benign tumor of striated muscle. Rhabdomyomas may be either "cardiac" or "extracardiac" . Extracardiac forms of rhabdomyoma are subclassified into three distinct types: Adult type, Fetal type, and Genital type.Cardiac rhabdomyomas are the most common primary tumor of the heart...
s (and rarely teratoma
Teratoma
A teratoma is an encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers. There are rare occasions when not all three germ layers are identifiable...
s). These other tumors of the heart are typically not pedunculated, however, and are more likely to infiltrate
Infiltration (medical)
Infiltration is the diffusion or accumulation of substances not normal to it or in amounts in excess of the normal. The material collected in those tissues or cells is called infiltrate.-Classification:...
the muscle of the heart. Cardiac magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI) can help non-invasively diagnose cardiac tumors. However, diagnosis usually requires examination of a tissue sample
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
by a pathologist.
Types
| Myxoma | Margin | Vascular pattern | Cellularity | Stroma Stroma (animal tissue) In animal tissue, stroma refers to the connective, supportive framework of a biological cell, tissue, or organ.The stroma in animal tissue is contrasted with the parenchyma.Examples include:* Stroma of iris... |
Staining characteristics | Recurrence rate | Image (see Histology Histology Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope... ) |
|---|---|---|---|---|---|---|---|
| Cutaneous myxoma Cutaneous myxoma A cutaneous myxoma, AKA superficial angiomyxoma, consists of a multilobulated myxoid mass containing stellate and/or spindled fibroblasts with pools of mucin forming cleft-like spaces. There is often a proliferation of blood vessels and an inflammatory infiltrate... or Superficial angiomyxoma |
Poor to moderately circumscribed, multilobular | Scattered thin-walled vessels | Moderately cellular, bland spindled and stellate cell Stellate cell In neuroscience, stellate cells are neurons with several dendrites radiating from the cell body giving them a star shaped appearance. The three most common stellate cells are the inhibitory interneurons found within the molecular layer of the cerebellum, excitatory spiny stellate interneurons and... s, variable inflammatory cell infiltrate |
Abundant mucin with clefts. Up to 30% have an associated epithelial component | Vimentin Vimentin Vimentin is a type III intermediate filament protein that is expressed in mesenchymal cells. IF proteins are found in all metazoan cells as well as bacteria. IF, along with tubulin-based microtubules and actin-based microfilaments, comprise the cytoskeleton... ; variable staining with CD34 CD34 CD34 molecule is a cluster of differentiation molecule present on certain cells within the human body. It is a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of stem cells to bone marrow extracellular matrix or directly to stromal cells... , factor XIIIA Factor XIII Factor XIII or fibrin stabilizing factor is an enzyme of the blood coagulation system that crosslinks fibrin.- Function :Factor XIII is a transglutaminase that circulates in the plasma as a heterotetramer of two catalytic A subunits and two carrier B subunits... , SMA, MSA and S-100 S-100 protein S-100 protein is a family of low molecular weight protein found in vertebrates characterized by two calcium binding sites of the helix-loop-helix conformation. There are at least 21 different types of S100 proteins... |
20–30% | |
| Intramuscular myxoma | Poorly circumscribed merges with surrounding muscle | Hypovascular variant; hypervascular variant | Hypocellular variant; hypercellular variant; bland spindle cells | Abundant mucin with cystic spaces. Hypercellular variant has strands of collagen | Vimentin; variable staining with actin Actin Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans... , desmin Desmin Desmin is a protein that in humans is encoded by the DES gene.Desmin is a type III intermediate filament found near the Z line in sarcomeres. It was first described in 1976, first purified in 1977, the gene was cloned in 1989, and the first knock-out mouse was created in 1996. Desmin is only... , CD34 |
None | |
| Juxta-articular myxoma | Poorly circumscribed infiltrates surrounding tissue | Focally vascular | Focally hypercellular, peripheral spindle cells with occasional atypical cells and mitoses | Abundant mucin, 89% of cases contain cystic spaces lined by fibrin or collagen | Vimentin; variable staining with actin, desmin, CD34 | 34% | |
| Aggressive angiomyxoma Angiomyxoma Angiomyxoma is a myxomatous tumor involving the blood vessels.It can affect the vulva and other parts of the pelvis.Aggressive angiomyxoma was originally described in 1983, but the term "angiomyxoma" dates back to at least 1952.... |
Infiltrative | Uniformly distributed medium-sized blood vessels often with prominent hyalinization | Low to moderately cellular, evenly distributed round, spindled or stellate cells | Loose myxoid to focally collagenous | Vimentin, desmin, SMA, MSA, estrogen and progesterone receptor | 36–72% | |
| Angiomyofibroblastoma | Well circumscribed | Abundant thin-walled blood vessels | Alternating hypercellular and hypocellular areas, perivascular condensations of spindled to epithelioid stromal cells | Collagenous to edematous with minimal mucin | Vimentin, desmin, CD34, estrogen and progesterone receptor Progesterone receptor The progesterone receptor also known as NR3C3 , is an intracellular steroid receptor that specifically binds progesterone... |
No recurrences reported, but rare cases of sarcomatous degeneration | |
| Superficial acral fibromyxoma Superficial acral fibromyxoma A superficial acral fibromyxoma is a type of Myxoma and is a rare cutaneous condition characterized by a mesenchymal neoplasm that typically occurs on the digits of middle-age adults.... |
Pushing to infiltrative | Mild to moderately accentuated vasculature | Moderately cellular, spindle and stellate cells with a storiform to fascicular pattern, variable mast cells | Myxoid to collagenous | CD34, EMA EMA Ema may refer to:* Ema , wooden plaques with prayers or wishes at Shintō shrines and Buddhist temples* Kemak people, also called Ema, an ethnic group in Timor* Ema, the local name of the Greater Rhea in Brazil... , CD99 CD99 CD99 antigen also known as MIC2 or single-chain type-1 glycoprotein is a protein that in humans is encoded by the CD99 gene. The protein has a mass of 32 kD... |
Recurrence rare and primarily for incompletely excised lesions | |
| Neurothekeoma Neurothekeoma Neurothekeoma is a Myxoma and is composed of cords and nests of large cells packed among collagen bundles in close proximity to small nerves.... (Nerve sheath myxoma) |
Well circumscribed, multilobular | Hypovascular | Moderately cellular, spindled cells in fascicles and whorls | Nests of cells separated by collagenous bundles | S-100, EMA | 47% if incompletely excised |
1.SMA, smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
actin
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
. 2.MSA, muscle-specific actin
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
. 3.EMA, epithelial membrane antigen
MUC1
Mucin 1, cell surface associated or polymorphic epithelial mucin is a mucin encoded by the MUC1 gene in humans. MUC1 is a proteoglycan with extensive O-linked glycosylation of its extracellular domain. Mucins line the apical surface of epithelial cells in the lungs, stomach, intestines, eyes and...
.
Symptoms
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
Interleukin 6
Interleukin-6 is a protein that in humans is encoded by the IL6 gene.IL-6 is an interleukin that acts as both a pro-inflammatory and anti-inflammatory cytokine. It is secreted by T cells and macrophages to stimulate immune response, e.g. during infection and after trauma, especially burns or other...
(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:
- DyspneaDyspneaDyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...
on exertion - Paroxysmal nocturnal dyspnea
- FeverFeverFever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
- Weight lossWeight lossWeight loss, in the context of medicine, health or physical fitness, is a reduction of the total body mass, due to a mean loss of fluid, body fat or adipose tissue and/or lean mass, namely bone mineral deposits, muscle, tendon and other connective tissue...
(see cachexiaCachexiaCachexia or wasting syndrome is loss of weight, muscle atrophy, fatigue, weakness, and significant loss of appetite in someone who is not actively trying to lose weight...
) - Lightheadedness or syncopeSyncope (medicine)Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...
(Loss of consciousness) - HemoptysisHemoptysisHemoptysis or haemoptysis is the expectoration of blood or of blood-stained sputum from the bronchi, larynx, trachea, or lungs Hemoptysis or haemoptysis is the expectoration (coughing up) of blood or of blood-stained sputum from the bronchi, larynx, trachea, or lungs Hemoptysis or haemoptysis ...
- Sudden death
- TachycardiaTachycardiaTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
or milder heartrate, ie 75 - 100 cycl/min
Treatment
Myxomas are usually removed surgically. The surgeon removes the myxoma, along with at least 5 surrounding millimeters of atrial septum. The septum is then repaired, using material from the pericardiumPericardium
The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.-Layers:...
.
See also
- Cutaneous myxomaCutaneous myxomaA cutaneous myxoma, AKA superficial angiomyxoma, consists of a multilobulated myxoid mass containing stellate and/or spindled fibroblasts with pools of mucin forming cleft-like spaces. There is often a proliferation of blood vessels and an inflammatory infiltrate...
- Carney complexCarney complexCarney complex, also known as LAMB syndrome and NAME syndrome is an autosomal dominant condition comprising myxomas of the heart and skin, hyperpigmentation of the skin , and endocrine overactivity It is distinct from Carney's triad...
- MyxomatosisMyxomatosisMyxomatosis is a disease that affects rabbits and is caused by the Myxoma virus. It was first observed in Uruguay in laboratory rabbits in the late 19th century. It was introduced into Australia in 1950 in an attempt to control the rabbit population...
- Primary tumors of the heartPrimary tumors of the heartThe primary tumors of the heart are 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...