dermatofibroma

{{Infobox medical condition (new)

| name = Dermatofibroma

| image = Histopathology of dermatofibroma.jpg

| caption = Histopathology of dermatofibroma, with basilar hyperpigmentation of the overlying epidermis (top right), and spindled fibroblasts with collagen entrapment. HE stain.

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| synonyms = Dermal dendrocytoma,{{cite book |author=Rapini, Ronald P. |author2=Bolognia, Jean L. |author3=Jorizzo, Joseph L. |title=Dermatology: 2-Volume Set |publisher=Mosby |location=St. Louis |year=2007 |isbn=978-1-4160-2999-1 }}{{page needed|date=June 2015}} Dermatofibroma, Fibrous dermatofibroma, Fibrous histiocytoma,{{cite book |author=Freedberg |display-authors=etal |year=2003 |title=Fitzpatrick's Dermatology in General Medicine |edition=6th |publisher=McGraw-Hill |isbn=978-0-07-138076-8 |page=668 }} Fibroma simplex, Nodular subepidermal fibrosis, and Sclerosing hemangioma)

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A dermatofibroma, or benign fibrous histiocytomas, is a benign nodule in the skin, typically on the legs, elbows or chest of an adult.{{cite book |last1=James |first1=William D. |last2=Elston |first2=Dirk |last3=Treat |first3=James R. |last4=Rosenbach |first4=Misha A. |last5=Neuhaus |first5=Isaac |title=Andrews' Diseases of the Skin: Clinical Dermatology |date=2020 |publisher=Elsevier |location=Edinburgh|isbn=978-0-323-54753-6 |pages=617–618 |edition=13th |chapter-url=https://books.google.com/books?id=UEaEDwAAQBAJ&dq=Dermal&pg=PA617 |language=en |chapter=28. Dermal and subcutaneous tumors}} It is usually painless.

It usually ranges from 0.2 to 2 cm in size but larger examples have been reported. It typically results from mild trauma such as an insect bite. Risk factors for developing multiple dermatofibromas include lupus, HIV, blood cancer and some medicines that weaken immunity.

It is usually diagnosed by its appearance, but a biopsy may be required. Other bumps such as granular cell tumor, melanoma, clear cell acanthoma and dermatofibrosis lenticularis disseminata may look similar. Usually no treatment is needed. It can remain unchanged for years but can resolve spontaneously.

Signs and symptoms

Dermatofibromas{{Cite web|url=https://rarediseases.info.nih.gov/diseases/9807/dermatofibroma|title=Dermatofibroma {{!}} Genetic and Rare Diseases Information Center (GARD) – an NCATS Program|website=rarediseases.info.nih.gov|language=en|access-date=2018-04-17}} are hard solitary slow-growing papules (rounded bumps) that appear in a variety of colours, usually brownish to tan. They are often elevated or pedunculated. A dermatofibroma is associated with the dimple sign; by applying lateral pressure, there is a central depression of the dermatofibroma. Although typical dermatofibromas cause little or no discomfort, itching and tenderness can occur. Dermatofibromas can be found anywhere on the body, but most often they are found on the legs and arms.{{DorlandsDict|three/000028730|dermatofibroma}} They occur more often in women; the male to female ratio is about 1:4. The age group in which they most commonly occur is 20 to 45 years.

Some physicians and researchers believe dermatofibromas form as a reaction to previous injuries such as insect bites or thorn pricks.{{EMedicine|article|1056742|Dermatofibroma}} They are composed of disordered collagen laid down by fibroblasts. Dermatofibromas are classed as benign skin lesions, meaning they are completely harmless, though they may be confused with a variety of subcutaneous tumours.{{cite journal |doi=10.5021/ad.2011.23.2.254 |pmid=21747634 |pmc=3130878 |title=Subcutaneous Dermatofibroma |journal=Annals of Dermatology |volume=23 |issue=2 |pages=254–7 |year=2011 |last1=Jung |first1=Kyu Dong |last2=Lee |first2=Dong-Youn |last3=Lee |first3=Joo-Heung |last4=Yang |first4=Jun-Mo |last5=Lee |first5=Eil-Soo }} Deep penetrating dermatofibromas may be difficult to distinguish, even histologically, from rare malignant fibrohistocytic tumours like dermatofibrosarcoma protuberans.{{cite journal |pmid=16740036 |year=2006 |last1=Hanly |first1=A. J. |title=High proliferative activity excludes dermatofibroma: Report of the utility of MIB-1 in the differential diagnosis of selected fibrohistiocytic tumors |journal=Archives of Pathology & Laboratory Medicine |volume=130 |issue=6 |pages=831–4 |last2=Jordà |first2=M |last3=Elgart |first3=G. W. |last4=Badiavas |first4=E |last5=Nassiri |first5=M |last6=Nadji |first6=M |doi=10.5858/2006-130-831-HPAEDR }}

Dermatofibromas typically have a positive buttonhole sign, or central dimpling in the center.{{cite book|last=Boursicot|first=Katharine|title=Oxford Assess and Progress: Clinical Specialties|date=24 January 2013|publisher=Oxford University Press|language=en|isbn=9780199657582|page=249}}

Diagnosis

= Immunohistochemical staining =

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Neoplasm

! CD34

! Stromelysin-3{{cite journal |doi=10.1111/j.1365-2133.2007.08033.x |pmid=17596171 |title=Stromelysin-3 expression in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans: Comparison with factor XIIIa and CD34 |journal=British Journal of Dermatology |volume=157 |issue=2 |pages=319–24 |year=2007 |last1=Kim |first1=H.J. |last2=Lee |first2=J.Y. |last3=Kim |first3=S.H. |last4=Seo |first4=Y.J. |last5=Lee |first5=J.H. |last6=Park |first6=J.K. |last7=Kim |first7=M.H. |last8=Cinn |first8=Y.W. |last9=Cho |first9=K.H. |last10=Yoon |first10=T.Y. |s2cid=7049937 }}

! Factor XIIIa

Dermatofibroma

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Dermatofibrosarcoma protuberans

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See also

References

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