dermatofibroma (benign fibrous histiocytoma)
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Introduction
Common, benign, button-like dermal nodule generally occurring on the extremities.
Etiology
- minor injury
- insect bites
- shaving injury
- folliculitis
- idiopathic
Epidemiology
- occurs in adults
- females > males
Pathology
- whorling fascicles of spindle cells
- variable increase in vascular spaces
- overlying epidermis is frequently hyperplastic
* histopathology images[4]
Clinical manifestations
- papule or nodule 3-10 mm in diameter
- may be domed or depressed below surface of surrounding skin
- borders ill-defined
- texture may be dull, shiny or scaly
- color variable: pink, tan, brown, dark brown, but generally darker at center, fading towards edges
- post-inflammatory hyper or hypopigmentation at center may occur secondary to repeated trauma
- firm papule or nodule
- dimple sign: lateral compression with thumb & index finger produces a depression or "dimple"
- distribution:
- lesions appear gradually over several months
- lesions may persist for years without increase in size
- lesions may regress spontaneously
Laboratory
- skin biopsy not necessary[2]
Differential diagnosis
- malignant melanoma
- scar
- blue nevus
- pilar cyst
- metastatic carcinoma
- Kaposi's sarcoma
- dermatofibrosarcoma protuberans
Management
- surgical excision
- generally not indicated
- resultant scar may be less acceptable than dermatofibroma
- indications:
- repeated trauma
- cosmetic disfigurement
- uncertainty in diagnosis
- cryotherapy with liquid nitrogen
More general terms
Additional terms
- blue nevus (dermal melanocytoma)
- cicatrix (scar)
- dermatofibrosarcoma protuberans
- Kaposi's sarcoma
- malignant fibrous histiocytoma (MFH, angiomatoid fibrous histiocytoma)
- melanoma
- trichilemmal cyst (pilar cyst, isthmus catagen cyst)
References
- ↑ Color Atlas and Synopsis of Clinical Dermatology, Common and Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY, 1997, pg 172-73
- ↑ 2.0 2.1 2.2 2.3 Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 18. American College of Physicians, Philadelphia 2012, 2015, 2018.
- ↑ 3.0 3.1 DermNet NZ. Dermatofibroma (images) http://www.dermnetnz.org/lesions/dermatofibroma.html
- ↑ 4.0 4.1 4.2 Pierson JC, Elston DM Medscape: Dermatofibroma http://emedicine.medscape.com/article/1056742-overview