Chorioangioma, or chorangioma, is a

benign tumor A benign tumor is a mass of Cell (biology), cells (tumor) that does not Cancer invasion, invade neighboring tissue or Metastasis, metastasize (spread throughout the body). Compared to Cancer, malignant (cancerous) tumors, benign tumors generally ...

placenta The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between ...

. It is a

hamartoma A hamartoma is a mostly benign, local malformation of cells that resembles a neoplasm of local tissue but is usually due to an overgrowth of multiple aberrant cells, with a basis in a systemic genetic condition, rather than a growth descended fr ...

-like growth in the

consisting of

blood vessel Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...

s, and is seen in approximately 0.5 to 1% pregnancies. It is mostly diagnosed ultrasonically in the second trimester of pregnancy. Large chorioangiomas are known to cause complications in pregnancy, while the smaller ones are asymptomatic.

Presentation

Most chorangiomas are not clinically significant, i.e. they do not have an adverse effect on placental function.

Complications

Large (greater than 4 or 5 cm.) or multiple chorioangiomas may lead to complication. The complications are

polyhydramnios Polyhydramnios is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in about 1% of pregnancies. It is typically diagnosed when the amniotic fluid index (AFI) is greater than 24 cm. There are two clini ...

, preterm labour,

hemolytic anemia Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). This most commonl ...

, fetal cardiomegaly, fetal

thrombocytopenia In hematology, thrombocytopenia is a condition characterized by abnormally low levels of platelets (also known as thrombocytes) in the blood. Low levels of platelets in turn may lead to prolonged or excessive bleeding. It is the most common coag ...

, intrauterine growth retardation, preeclampsia, abruption of placenta and congenital anomalies.

Pathogenesis

The origin of chorioangioma is from primitive chorionic

mesenchyme Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood, or bone. The interactions between mesenchyme and epithelium help to form nearly ever ...

. It develops when the

s and stroma undergo rapid proliferation independent of the surrounding tissue. Based on

histological Histology, also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...

features, chorioangioma is classified by Marchetti into three types: *Cellular type : This type is immature and contains mostly cellular elements packed compactly. * Angiomatous (vascular) type : This is the most common type of choriocarcinoma. It is distinguished by the presence of numerous small blood vessels. * Degenerative type : This is the mature type with degenerative changes. Each type is believed to represent a phase of tumor development. Chorioangioma has no

malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

potential.

Diagnosis

Most chorioangiomas are

asymptomatic Asymptomatic (or clinically silent) is an adjective categorising the medical conditions (i.e., injuries or diseases) that patients carry but without experiencing their symptoms, despite an explicit diagnosis (e.g., a positive medical test). P ...

. They are generally picked up in second trimester scan. Chorioangioma is seen as a hypo- or hyperechoic circumscribed mass that is distinct from the placenta at gray-scale US examination. Large lesions may contain fibrous septa. It is seen protruding into the amniotic cavity near the insertion of the cord. Doppler examination shows anechoic cystic areas, with pulsatile flow in spectral analysis. Some chorioangiomas may be solid masses, and may not be identifiable in gray-scale imaging. Therefore, the investigation of choice is Colour Doppler, which also distinguishes it from placental hematoma. They can also be detected with

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

. Histologically, chorioangiomas consist of abundant vascular channels and may be cellular.

Management

Expectant management is recommended for chorioangioma as majority of them are asymptomatic. Large tumors are monitored with ultrasonogram every 1–2 weeks. In case of maternal or foetal complications, possible interventions are serial foetal transfusions, fetoscopic laser coagulation of vessels supplying the tumor, endoscopic surgical devascularization and chemosclerosis using absolute alcohol.

Prognosis

Large chorioangiomas with decreased echogenicity, decreased tumor volume and decreased blood flow in colour doppler images are may undergo spontaneous infarction. When chorioangiomas have deceased

blood flow Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynamics, dynamics of blood flow. The circulatory system is controlled by homeostasis, homeostatic mechanisms of autoregulation, just as hydrau ...

, fetal hemodynamics and clinical outcome are found to be improved.

Epidemiology

It is the most common tumor of the placenta. Chorioangiomas over the size of 5 cm in diameter are rare, and occur at a rate of 1:3500 to 1:16,000 births. Smaller chorioangiomas are more frequent, with an incidence of 14‑139:10,000 births. However, many small chorioangiomas may not be sonologically visible and hence go unreported. In a clinical study, more than half of all tumors were discovered only by histological techniques.

History

Chorioangioma was first described by Clarke in 1798.

References

External links

Chorangioma (pathweb.uchc.edu)Chorangioma (humpath.com)
{{Vascular tumors Gynaecological neoplasia Health issues in pregnancy