Dysplasia is any of various types of abnormal growth or development of cells (microscopic scale) or organs (macroscopic scale), and the abnormalhistology or anatomical structure(s) resulting from such growth.[1] Dysplasias on a mainly microscopic scale includeepithelial dysplasia andfibrous dysplasia of bone. Dysplasias on a mainly macroscopic scale includehip dysplasia,myelodysplastic syndrome, andmulticystic dysplastic kidney.
In one of the modernhistopathological senses of the term, dysplasia is sometimes differentiated from other categories of tissue change includinghyperplasia,metaplasia, andneoplasia, and dysplasias are thus generally notcancerous. An exception is that the myelodysplasias include a range ofbenign,precancerous, and cancerous forms. Various other dysplasias tend to be precancerous. The word's meanings thus cover a spectrum of histopathological variations.
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Epithelial dysplasia consists of an expansion of immature cells (such as cells of theectoderm), with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an earlyneoplastic 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-situneoplasm.[citation needed]
Dysplasia, in which cell maturation and differentiation are delayed, can be contrasted withmetaplasia, in which cells of one mature,differentiated type are replaced by cells of another mature, differentiated type.[citation needed]
Myelodysplastic syndromes (MDS) are a group ofcancers in which immatureblood cells in thebone marrow do not mature and therefore do not become healthy blood cells.[2] Problems with blood cell formation result in some combination oflow red blood cells,low platelets, andlow white blood cells.[2] Some types have an increase in immature blood cells, calledblasts, in the bone marrow orblood.[2]
Fibrous dysplasia of bone is a disorder where normalbone andmarrow is replaced withfibrous tissue, 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.[3]
Hip dysplasia is an abnormality of thehip joint where the socket portion does not fully cover the ball portion, resulting in an increased risk forjoint dislocation.[4] Hip dysplasia may occur at birth or develop in early life.[4] Regardless, it does not typically produce symptoms in babies less than a year old.[5] Occasionally one leg may be shorter than the other.[4] The left hip is more often affected than the right.[5] Complications without treatment can includearthritis, limping, andlow back pain.[5]
Multicystic dysplastic kidney (MCDK) is a condition that results from the malformation of thekidney duringfetal development. The kidney consists of irregular cysts of varying sizes. Multicystic dysplastic kidney is a common type of renalcystic disease, and it is a cause of anabdominal mass in infants.[6]
FromAncient Greek δυσ-dys- 'bad' or 'difficult' and πλάσιςplasis 'formation'. The equivalentsurface analysis, in parallel withclassical compounds, isdys- +-plasia.[citation needed]
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