Dysplasia is any of various types of abnormal growth or development of cells (

microscopic scale The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens (optics), lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as ...

) or organs (

macroscopic scale The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical instruments. It is the opposite of microscopic. Overview When applied to physical phenom ...

), and the abnormal

histology 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 ...

or anatomical structure(s) resulting from such growth. Dysplasias on a mainly microscopic scale include

epithelial dysplasia Epithelial dysplasia, a term becoming increasingly referred to as intraepithelial neoplasia, is the sum of various disturbances of epithelium, epithelial proliferation and differentiation as seen microscopically. Individual cellular features of d ...

and

fibrous dysplasia of bone Fibrous dysplasia is a very rare nonhereditary genetic disorder where normal bone and marrow is replaced with fibrous tissue, resulting in formation of bone that is weak and prone to expansion. As a result, most complications result from fractu ...

. Dysplasias on a mainly macroscopic scale include

hip dysplasia Hip dysplasia is an abnormality of the hip joint where the socket portion does not fully cover the ball portion, resulting in an increased risk for joint dislocation. Hip dysplasia may occur at birth or develop in early life. Regardless, it doe ...

myelodysplastic syndrome A myelodysplastic syndrome (MDS) is one of a group of cancers in which blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may includ ...

, and

multicystic dysplastic kidney Multicystic dysplastic kidney (MCDK) is a condition that results from the malformation of the kidney during fetal development. The kidney consists of irregular cysts of varying sizes. Multicystic dysplastic kidney is a common type of renal cyst ...

. In one of the modern

histopathological Histopathology (compound of three Greek language, Greek words: 'tissue', 'suffering', and ''-logy, -logia'' 'study of') is the light microscope, microscopic examination of Tissue (biology), tissue in order to study the manifestations of dis ...

senses of the term, dysplasia is sometimes differentiated from other categories of tissue change including

hyperplasia Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of Tissue (biology), organic tissue that results from ...

metaplasia Metaplasia () is the transformation of a cell type to another cell type. The change from one type of cell to another may be part of a normal maturation process, or caused by some sort of abnormal stimulus. In simplistic terms, it is as if the ...

, and

neoplasia A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

, and dysplasias are thus generally not

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

ous. An exception is that the myelodysplasias include a range of

benign 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 ...

precancerous A precancerous condition is a condition, tumor or lesion involving abnormal cells which are associated with an increased risk of developing into cancer. Clinically, precancerous conditions encompass a variety of abnormal tissues with an increase ...

, and cancerous forms. Various other dysplasias tend to be precancerous. The word's meanings thus cover a spectrum of histopathological variations.

Microscopic scale

Epithelial dysplasia

Epithelial dysplasia consists of an expansion of immature cells (such as cells of the

ectoderm The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the o ...

), with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early

neoplastic A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

process. The term dysplasia is typically used when the cellular abnormality is restricted to the originating tissue, as in the case of an early, ''in-situ''

neoplasm A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

. Dysplasia, in which cell maturation and differentiation are delayed, can be contrasted with

, in which cells of one mature, differentiated type are replaced by cells of another mature, differentiated type.

Myelodysplastic syndrome

''Myelodysplastic syndromes'' (''MDS'') are a group of

s in which immature

blood cell A blood cell (also called a hematopoietic cell, hemocyte, or hematocyte) is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), ...

s in the

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It i ...

do not mature and therefore do not become healthy blood cells. Problems with blood cell formation result in some combination of low red blood cells,

low platelets 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 coa ...

, and

low white blood cells Leukopenia () is a decrease in the number of white blood cells (leukocytes). It places individuals at increased risk of infection as white blood cells are the body's primary defense against infections. Signs and symptoms Symptoms may include: * sk ...

. Some types have an increase in immature blood cells, called

blasts In cell biology, precursor cells—also called blast cells—are partially differentiated, or intermediate, and are sometimes referred to as progenitor cells. A precursor cell is a stem cell with the capacity to differentiate into only one cell t ...

, in the bone marrow or

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

Fibrous dysplasia of bone

Fibrous dysplasia of bone is a disorder where normal

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

and marrow is replaced with

fibrous tissue Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesode ...

, resulting in formation of bone that is weak and prone to expansion. As a result, most complications result from fracture, deformity, functional impairment and pain.

Macroscopic scale

Hip dysplasia

''Hip dysplasia'' is an abnormality of the

hip joint In vertebrate anatomy, the hip, or coxaLatin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) (: ''coxae'') in medical terminology, refers to either an anatomical region or a joint o ...

where the socket portion does not fully cover the ball portion, resulting in an increased risk for

joint dislocation A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, where two or more bones meet. A partial dislocation is referred to as a subluxation. Dislocations are commonly caused by sudden Trauma (medic ...

. Hip dysplasia may occur at birth or develop in early life. Regardless, it does not typically produce symptoms in babies less than a year old. Occasionally one leg may be shorter than the other. The left hip is more often affected than the right. Complications without treatment can include

arthritis Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...

, limping, and

low back pain Low back pain or wiktionary:lumbago#Etymology, lumbago is a common musculoskeletal disorders, disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can var ...

Multicystic dysplastic kidney

''Multicystic dysplastic kidney'' (''MCDK'') is a condition that results from the malformation of the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

during

fetal development Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...

. The kidney consists of irregular cysts of varying sizes. Multicystic dysplastic kidney is a common type of renal

cystic A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubb ...

disease, and it is a cause of an

abdominal mass An abdominal mass is any localized enlargement or swelling in the human abdomen. Depending on its location, the abdominal mass may be caused by an enlarged liver (hepatomegaly), enlarged spleen (splenomegaly), protruding kidney, a pancreatic mass, ...

in infants.

Etymology

From

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

δυσ- ''dys-'' 'bad' or 'difficult' and πλάσις ''plasis'' 'formation'. The equivalent

surface analysis Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations. Weather maps are created by plotting or tra ...

, in parallel with

classical compound Neoclassical compounds are compound words composed from combining forms (which act as affixes or stems) derived from Classical_language#Classical_studies, classical languages (classical Latin or ancient Greek) root (linguistics), roots. Neo-Lati ...

s, is '' dys-'' + '' -plasia''.

Microscopic scale

Epithelial dysplasia

Myelodysplastic syndrome

Fibrous dysplasia of bone

Macroscopic scale

Hip dysplasia

Multicystic dysplastic kidney

Etymology

See also

References

Further reading