Dysplasia

{{Short description|Abnormal development, at macroscopic or microscopical level}} {{About|the noncancerous and precancerous changes in cells and tissues|the clinical condition affecting the hip joint|Hip dysplasia}} {{Distinguish|Dyscrasia}} thumb|Normal squamous cells thumb|Dysplastic cells '''Dysplasia''' is any of various types of abnormal growth or development of cells (microscopic scale) or organs (macroscopic scale), and the abnormal histology or anatomical structure(s) resulting from such growth.<ref>{{cite web|url=https://www.merriam-webster.com/dictionary/dysplasia|title=Definition of dysplasia|website=Merriam-Webster dictionary|access-date=2019-09-09}}</ref> Dysplasias on a mainly microscopic scale include epithelial dysplasia and fibrous dysplasia of bone. Dysplasias on a mainly macroscopic scale include hip dysplasia, myelodysplastic syndrome, and multicystic dysplastic kidney.

In one of the modern histopathological senses of the term, dysplasia is sometimes differentiated from other categories of tissue change including hyperplasia, metaplasia, and neoplasia, and dysplasias are thus generally not cancerous. An exception is that the myelodysplasias include a range of benign, precancerous, 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 === {{Main|Epithelial dysplasia}} {{-plasia}} Epithelial dysplasia consists of an expansion of immature cells (such as cells of the ectoderm), with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic 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.{{citation needed|date=September 2022}}

Dysplasia, in which cell maturation and differentiation are delayed, can be contrasted with metaplasia, in which cells of one mature, differentiated type are replaced by cells of another mature, differentiated type.{{citation needed|date=September 2022}}

=== Myelodysplastic syndrome === {{Main|Myelodysplastic syndrome}} ''Myelodysplastic syndromes'' (''MDS'') are a group of cancers in which immature blood cells in the bone marrow do not mature and therefore do not become healthy blood cells.<ref name=NCI2015>{{cite web |title=Myelodysplastic Syndromes Treatment (PDQ®)–Patient Version |url=https://www.cancer.gov/types/myeloproliferative/patient/myelodysplastic-treatment-pdq#section/all |publisher=NCI|access-date=27 October 2016 |archive-url=https://web.archive.org/web/20161005015558/https://www.cancer.gov/types/myeloproliferative/patient/myelodysplastic-treatment-pdq |date=12 August 2015|archive-date =5 October 2016}}</ref> Problems with blood cell formation result in some combination of low red blood cells, low platelets, and low white blood cells.<ref name=NCI2015/> Some types have an increase in immature blood cells, called blasts, in the bone marrow or blood.<ref name=NCI2015/>

=== Fibrous dysplasia of bone === {{Main|Fibrous dysplasia of bone}} Fibrous dysplasia of bone is a 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 fracture, deformity, functional impairment and pain.<ref name=":0">{{Cite book | vauthors = Boyce AM, Florenzano P, de Castro LF, Collins MT | chapter = Fibrous Dysplasia/McCune–Albright Syndrome| chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK274564/ | title = Gene Reviews |publisher = University of Washington, Seattle |date = February 2015 |location = Seattle (WA) |pmid = 25719192 | veditors = Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJ, Mirzaa G, Amemiya A }}</ref>

== Macroscopic scale ==

=== Hip dysplasia === {{Main|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.<ref name=OA2013>{{cite web |url=http://orthoinfo.aaos.org/topic.cfm?topic=A00347 |title=Developmental Dislocation (Dysplasia) of the Hip (DDH) |date=October 2013 | publisher = American Academy of Orthopaedic Surgeons }}</ref> Hip dysplasia may occur at birth or develop in early life.<ref name=OA2013/> Regardless, it does not typically produce symptoms in babies less than a year old.<ref name=Shaw2017/> Occasionally one leg may be shorter than the other.<ref name=OA2013/> The left hip is more often affected than the right.<ref name=Shaw2017/> Complications without treatment can include arthritis, limping, and low back pain.<ref name=Shaw2017>{{cite journal | vauthors = Shaw BA, Segal LS | title = Evaluation and Referral for Developmental Dysplasia of the Hip in Infants | journal = Pediatrics | volume = 138 | issue = 6 | pages = e20163107 | date = December 2016 | pmid = 27940740 | doi = 10.1542/peds.2016-3107 | doi-access = free }}</ref>

===Multicystic dysplastic kidney=== {{Main|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 cystic disease, and it is a cause of an abdominal mass in infants.<ref>{{EMedicine|article|411365|Multicystic Dysplastic Kidney Imaging}}</ref>

==Etymology== From Ancient Greek δυσ- ''dys-'' 'bad' or 'difficult' and πλάσις ''plasis'' 'formation'. The equivalent surface analysis, in parallel with classical compounds, is ''dys-'' + ''-plasia''.{{citation needed|date=September 2022}}

== References == {{reflist|30em}}

== Further reading == {{refbegin}} * {{ cite book | veditors = Weidner N, Cote R, Suster S, Weiss L | title = Modern Surgical Pathology | publisher = W.B. Saunders | location = London | year = 2003 | isbn = 978-0-7216-7253-3 | oclc = 50244347 }} * {{ cite book | veditors = Cotran RS, Kumar V, Collins T | title = Robbins Pathologic Basis of Disease | edition = 6th | publisher = W.B. Saunders | location =London | year = 1999 | isbn = 978-0-7216-7335-6 | oclc = 39465455 }} {{refend}}

Category:Oncology Category:Histopathology Category:Induced stem cells