:Pilomatricoma

{{Infobox medical condition (new)

| name = Pilomatricoma

| synonyms = Calcifying epithelioma of Malherbe,{{cite book |last1=Rapini |first1=Ronald P. |last2=Bolognia |first2=Jean L. |last3=Jorizzo |first3=Joseph L. |title=Dermatology: 2-Volume Set |publisher=Mosby |location=St. Louis |year=2007 |isbn=978-1-4160-2999-1 }}{{page needed|date=July 2016}} Malherbe calcifying epithelioma, and Pilomatrixoma

| image = Histopathology of pilomatricoma, high magnification, annotated.jpg

| caption = Histopathology of pilomatricoma, high magnification, H&E stain, showing the characteristic components of basaloid cells and ghost cells.

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Pilomatricoma is a benign skin tumor derived from the hair matrix.{{cite book |editor1-first=William Daniel |editor1-last=James |editor2-first=Timothy G. |editor2-last=Berger |editor3-first=Dirk M. |editor3-last=Elston |title=Andrews' Diseases of the Skin: Clinical Dermatology |publisher=Saunders Elsevier |year=2006 |page=670 |isbn=978-0-8089-2351-0 }}{{cite journal |last1=Levy |first1=Jaime |last2=Ilsar |first2=Michael |last3=Deckel |first3=Yael |last4=Maly |first4=Alexander |last5=Anteby |first5=Irene |last6=Pe'er |first6=Jacob |title=Eyelid Pilomatrixoma: A Description of 16 cases and a Review of the Literature |journal=Survey of Ophthalmology |volume=53 |issue=5 |pages=526–35 |year=2008 |pmid=18929763 |doi=10.1016/j.survophthal.2008.06.007 }} These neoplasms are relatively uncommon and typically occur on the scalp, face, and upper extremities. Clinically, pilomatricomas present as a subcutaneous nodule or cyst with unremarkable overlying epidermis that can range in size from 0.5 to 3.0 cm, but the largest reported case was 24 cm.{{cite journal |last1=Gongidi |first1=P. |last2=Meshekow |first2=J. |last3=Holdbrook |first3=T. |last4=Germaine |first4=P. |title=Giant Pilomatrixoma Presenting in the Posterior Thorax, a Rare Location and the Largest Described |journal=Case Reports in Radiology |volume=2015 |pages=590742 |year=2015 |pmid=25763287 |pmc=4339831 |doi=10.1155/2015/590742 |doi-access=free }}

Presentation

=Associations=

Pilomatricomas have been observed in a variety of genetic disorders including Turner syndrome, myotonic dystrophy, Rubinstein–Taybi syndrome, trisomy 9, and Gardner syndrome.{{cite journal |last1=Cooper |first1=Philip H. |last2=Fechner |first2=Robert E. |title=Pilomatricoma-like changes in the epidermal cysts of Gardner's syndrome |journal=Journal of the American Academy of Dermatology |volume=8 |issue=5 |pages=639–644 |year=1983 |pmid=6863619 |doi=10.1016/S0190-9622(83)70071-X }} It has been reported that the prevalence of pilomatricomas in Turner syndrome is 2.6%.

Hybrid cysts that are composed of epidermal inclusion cysts and pilomatricoma-like changes have been repeatedly observed in Gardner syndrome.{{cite journal |last1=Narisawa |first1=Yutaka |last2=Kohda |first2=Hiromu |title=An Unusual Hybrid Cyst in Gardner's Syndrome with Partial Differentiation toward the Inner Root Sheath |journal=The Journal of Dermatology |volume=16 |issue=6 |pages=492–495 |year=1989 |pmid=2628457 |doi=10.1111/j.1346-8138.1989.tb01591.x |s2cid=11344468 }}{{cite journal |last1=Rütten |first1=A. |last2=Wenzel |first2=P. |last3=Goos |first3=M. |title=Gardner-Syndrom mit pilomatrixomartigen Haarfollikelzysten |trans-title=Gardner syndrome with pilomatrixoma-like hair follicle cysts |language=de |journal=Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und Verwandte Gebiete |volume=41 |issue=6 |pages=326–328 |year=1990 |id={{INIST|19291018}} |pmid=2380070 }}{{cite journal |last1=Narisawa |first1=Yutaka |last2=Kohda |first2=Hiromu |title=Cutaneous cysts of Gardner's syndrome are similar to follicular stem cells |journal=Journal of Cutaneous Pathology |volume=22 |issue=2 |pages=115–121 |year=1995 |pmid=7560342 |doi=10.1111/j.1600-0560.1995.tb01392.x |s2cid=5572492 }}{{cite journal |last1=Urabe |first1=Kazunori |last2=Xia |first2=Jianxin |last3=Masuda |first3=Teiichi |last4=Moroi |first4=Yoichi |last5=Furue |first5=Masutaka |last6=Matsumoto |first6=Takayuki |title=Pilomatricoma-Like Changes in the Epidermoid Cysts of Gardner Syndrome with an APC Gene Mutation |journal=The Journal of Dermatology |volume=31 |issue=3 |pages=255–257 |year=2004 |pmid=15187352 |doi=10.1111/j.1346-8138.2004.tb00669.x |s2cid=29916492 }} This association has prognostic import, since cutaneous findings in children with Gardner syndrome generally precede colonic polyposis.{{citation needed|date=July 2016}}

Histologic features

File:Pilomatrixoma - high mag.jpg of a pilomatricoma showing the characteristic "ghost" cells (anucleate squamous cells), benign viable squamous cells and multi-nucleated giant cells. H&E stain.]]

The characteristic components of a pilomatricoma include a stroma of fibrovascular connective tissue

surrounding irregularly shaped, lobulated islands containing basaloid cells (being darkly stained, round or elongated, with indistinct cell borders and minimal cytoplasm, with nuclei being round to ovoid, deeply basophilic and generally prominent nucleoli), which abruptly or gradually transitions into ghost cells (having abundant, pale, eosinophilic cytoplasm, well defined cell borders and a central clear area, but only faint traces of nuclear material), which in turn may transition into keratinaceous to amorphous necrosis.{{cite web|url=http://atlasgeneticsoncology.org/Tumors/PilomatricomaID5153.html|title=Skin: Pilomatricoma|website=Atlas of Genetics and Cytogenetics in Oncology and Haematology|date=2009-06-01|author=Punnya V Angadi}}

The presence of calcifications with foreign-body giant cells is common within the tumors.{{cite book |editor1-first=David E. |editor1-last=Elder |year=2014 |title=Lever's Histopathology of the Skin |edition=11th |pages=440, 1056 |publisher=Wolters Kluwer |isbn=978-1-4511-9037-3 }}

Pathogenesis

Pilomatricoma is associated with high levels of beta-catenin caused by either a mutation in the APC gene or a stabilizing mutation in the beta-catenin gene, CTNNB1. A high level of beta-catenin increases cell proliferation, inhibits cell death, and ultimately leads to neoplastic growth.{{cite journal |last1=Glanz |first1=Steven M. |last2=Kessler |first2=Harvey P. |last3=Eskin |first3=Thomas A. |last4=Liu |first4=Chen |last5=Hassanein |first5=Ashraf M. |title=b-Catenin Is Expressed Aberrantly in Tumors Expressing Shadow Cells Pilomatricoma, Craniopharyngioma, and Calcifying Odontogenic Cyst |journal=American Journal of Clinical Pathology |volume=120 |issue=5 |pages=732–6 |year=2003 |pmid=14608900 |doi=10.1309/EALEG7LD6W7167PX |doi-access=free }}

See also

References

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