| Myxoma | |
|---|---|
 | |
| Micrograph of an atrial myxoma. H&E stain. | |
| Specialty | Oncology  |
A myxoma (New Latin from Greek muxa 'mucus') is a myxoid tumor of primitive connective tissue. [1] It is most commonly found in the heart (and is the most common primary tumor of the heart in adults) but can also occur in other locations.
Table below: [2]
| Myxoma | Margin | Vascular pattern | Cellularity | Stroma | Staining characteristics | Recurrence rate | Image (see Histology) |
|---|---|---|---|---|---|---|---|
| Cutaneous myxoma or Superficial angiomyxoma | Poor to moderately circumscribed, multilobular | Scattered thin-walled vessels | Moderately cellular, bland spindled and stellate cells, variable inflammatory cell infiltrate | Abundant mucin with clefts. Up to 30% have an associated epithelial component | Vimentin; variable staining with CD34, factor XIIIA, SMA 1 , MSA 2 and S-100 | 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, desmin, 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 | 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 1 , MSA 2 , 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 | No recurrences reported, but rare cases of sarcomatous degeneration | |
| Superficial acral fibromyxoma | 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 [ clarification needed ] 3 , CD99 | Recurrence rare and primarily for incompletely excised lesions | |
| Neurothekeoma (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 3 | 47% if incompletely excised |  |
1. ^ SMA, smooth muscle actin. 2. ^ MSA, muscle-specific actin. 3. ^ EMA, epithelial membrane antigen.
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. [3] [4] High levels of IL-6 may be associated with a higher risk of embolism of the myxoma. [5]
Symptoms of a cardiac myxoma include: [6]
Myxoma is a rare, benign stromal tumor of mesenchymal origin often confused with other conjunctival stromal tumors. Conjunctival myxomas are thought to originate in Tenon's capsule and can masquerade as conjunctival lymphoma, lymphangioma, ocular surface squamous neoplasia (OSSN), or amelanotic melanoma. [7]
Myxomas are usually located in either the left or right atrium of the heart; about 86 percent occur in the left atrium. [8]
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. [9]
An atrial myxoma may create an extra heart sound, 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.[ citation needed ]
The differential diagnosis include other cardiac tumors such as lipomas and rhabdomyomas (and rarely teratomas). 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.[ citation needed ]
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 pericardium.[ citation needed ]
Cardiac myxomas predominantly appear in females in their 30s to 40s. Myxomas are the most common primary cardiac tumor affecting adults, [9] accounting for one quarter to half of primary cardiac tumors seen in clinical practice. [10]
The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, and conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact.
Hypertrophic cardiomyopathy is a condition in which muscle tissues of the heart become thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems. Specifically, within the bundle branches that conduct impulses through the interventricular septum and into the Purkinje fibers, as these are responsible for the depolarization of contractile cells of both ventricles.
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA).
A rhabdomyoma is a benign tumor of striated muscle. Rhabdomyomas may be either cardiac or extracardiac. Extracardiac forms of rhabdomyoma are sub-classified into three distinct types: adult type, fetal type, and genital type.
The interatrial septum is the wall of tissue that separates the right and left atria of the heart.
Carney complex and its subsets LAMB syndrome and NAME syndrome are autosomal dominant conditions comprising myxomas of the heart and skin, hyperpigmentation of the skin (lentiginosis), and endocrine overactivity. It is distinct from Carney's triad. Approximately 7% of all cardiac myxomas are associated with Carney complex.
In the heart's conduction system, Bachmann's bundle is a branch of the anterior internodal tract that resides on the inner wall of the left atrium. It is a broad band of cardiac muscle that passes from the right atrium, between the superior vena cava and the ascending aorta. Bachmann's bundle is, during normal sinus rhythm, the preferential path for electrical activation of the left atrium. It is therefore considered to be part of the "atrial conduction system" of the heart.
Mitral valve replacement is a procedure whereby the diseased mitral valve of a patient's heart is replaced by either a mechanical or tissue (bioprosthetic) valve.
Primary tumors of the heart are extremely rare tumors that arise from the normal tissues that make up the heart. The incidence of primary cardiac tumors has been found to be approximately 0.02%. 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. Metastatic tumors to the heart are about 20 times more common than primary cardiac tumors.
Heart cancer is an extremely rare form of cancer that is divided into primary tumors of the heart and secondary tumors of the heart.
A myxoma is a rare benign tumor of the heart. Myxomata are the most common primary cardiac tumor in adults, and are most commonly found within the left atrium near the valve of the fossa ovalis. Myxomata may also develop in the other heart chambers. The tumor is derived from multipotent mesenchymal cells. Cardiac myxoma can affect adults between 30 and 60 years of age.
Myocardial rupture is a laceration of the ventricles or atria of the heart, of the interatrial or interventricular septum, or of the papillary muscles. It is most commonly seen as a serious sequela of an acute myocardial infarction.
Angiomyxoma is a myxoid tumor involving the blood vessels.
A Neurothekeoma (NT) is a type of rare benign cutaneous tumor that usually develops on the head and neck. They often occur in the second and early third decades of life and tend to afflict women more frequently than men. First described by Gallager and Helwig, who proposed the term in order to reflect the presumed origin of the lesion from nerve sheath. Microscopically, the lesions described closely resembled the tumor, "nerve sheath myxoma (NSM)", an entity first described by Harkin and Reed. The latter had, through the years, been variously described as "bizarre cutaneous neurofibroma", "myxoma of nerve sheath", and "pacinian neurofibroma".
A cutaneous myxoma, or superficial angiomyxoma, consists of a multilobulated myxoid mass containing stellate or spindled fibroblasts with pools of mucin forming cleft-like spaces. There is often a proliferation of blood vessels and an inflammatory infiltrate. Staining is positive for vimentin, negative for cytokeratin and desmin, and variable for CD34, Factor VIIIa, SMA, MSA and S-100.
Endometrial stromal sarcoma is a malignant subtype of endometrial stromal tumor arising from the stroma of the endometrium rather than the glands. There are three grades for endometrial stromal tumors, as follows. It was previously known as endolymphatic stromal myosis because of diffuse infiltration of myometrial tissue or the invasion of lymphatic channels.
Cardiac fibroma, also known as cardiac fibromatosis, cardiac fibrous hamartoma, fibroelastic hamartoma of heart and fibroma of heart is the second highest type of primary cardiac tumor seen in infants and children. This benign tumor made by connective tissue and fibroblast is largely observed in the ventricles of the heart. The left ventricle is the most common location of cardiac fibroma and accounts for approximately 57% of cardiac fibroma cases followed by the right ventricle with 27.5% of cases. Symptoms of the disease 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. Therefore the cause of cardiac fibroma is unexplained but has been associated with Gorlin Syndrome. Echocardiography is the primarily diagnostic method used to detect if an individual has cardiac fibroma. Resection of the tumor is recommended however heart transplantation is done if surgery is not possible. Overall prognosis of resection is favorable and the chance of recurrence is scarcely reported.
Tegumental angiomyxoma-neurothekeoma is a syndrome, an acronym, and eponym proposed by Malaysian ophthalmologist of Chinese Descent, Tan Aik Kah. Angiomyxomas are associated with LAMB syndrome, NAME syndrome and Carney syndrome.
A myxoid tumor is a connective tissue tumor with a "myxoid" background, composed of clear, mucoid substance.
Ectomesenchymal chondromyxoid tumor (ECT) is a benign intraoral tumor with presumed origin from undifferentiated (ecto)mesenchymal cells. There are some who think it is a myoepithelial tumor type.