Dermatofibroma
Introduction
Dermatofibromas (DFs) are prevalent cutaneous lesions that most frequently affect young to middle-aged adults, with a slight predominance in females. Clinically, dermatofibromas appear as firm, single or multiple papules/nodules with a relatively smooth surface and predilection for the lower extremities. Characteristically, upon lateral compression of the skin surrounding dermatofibromas, the tumors tend to pucker inward producing a dimple-like depression in the overlying skin; a feature known as the dimple or Fitzpatrick’s sign.
Dermoscopy features [1] [2]
Classic dermoscopic features
- Delicate pigment network: light-to-medium pigment network, brown in color, with a fine and delicate quality, which gradually fades into the surrounding skin and is usually located at the periphery of the lesion.
- Central scar-like white patch: an irregularly outlined and sharply demarcated white area in the center of the lesion. In nonpolarized light dermoscopy appears as a white scar-like area and in polarized light dermoscopy as a bright white area with or without bright white linear streaks (shiny white lines).
Additional dermoscopic features
- Ring-like or donut-shaped globules: the pigment network located toward the center of the lesion often ceases to look like a reticulated mesh but rather begins to resemble “ring-like” globular structures.
- White network : white lines surrounding small islands of brown pigment or surrounding globule-like (i.e., “ring-like”) structures.
- Homogenous areas with brown color.
- Vascular structures: erythema, dotted vessels, comma vessels, and hairpin vessels. Less frequently, glomerular vessels, linear–irregular vessels, linear vessels in a radial arrangement, and polymorphous/atypical vessels are visible.
- Rarely comedo-like openings, scale, ulceration, peripheral collarette fissures, ridges and mamillated surface.
Dermoscopy patterns [3] [4]
The different dermoscopic features of dermatofibroma are combined into ten different typical dermoscopic patterns and one atypical pattern.
Typical dermoscopic patterns
- Peripheral delicate pigment network and central white scar-like patch.
This "stereotypical" dermoscopic pattern is seen in most cases of dermatofibroma and has been reported in 18-35% of DFs.
- Delicate pigment network throughout - 3-15% of DFs.
- Peripheral delicate pigment network and central white network - 5-9% of DFs.
- Peripheral delicate pigment network and central homogenous pigmentation - 4-5% of DFs.
- White network throughout - 2% of DFs.
- Homogenous pigmentation throughout - 5-11% of DFs.
- White scar-like patch throught- 4-6% of DFs.
- Multiple focal white scar-like patches - 6-8% of DFs.
- Peripheral homogenous pigmentation and central white scar-like patch - 7-8% of DFs.
- Peripheral homogenous pigmentation and central white network - 5-8% of DFs.
Atypical dermoscopic patterns
Dermatofibromas showing atypical pigment network, atypical scar-like patch, atypical homogeneous pigmentation or their irregular distribution within the lesion. The atypical pattern can be further subdivided into: (1) 'Melanoma-like'; (2) 'vascular tumor-lie'; (3) 'basal cell carcinoma-like'; (4) 'collision tumor-like'; (5) 'psoriasis-like'.
Dermatofibroma variants
Hemosiderotic or aneurysmal dermatofibroma
Hemosiderotic or aneurysmal dermatofibroma usually manifests with a multi-component or atypical dermoscopic pattern with central bluish/reddish homogenous areas in combination with white structures, peripheral delicate pigment network, and vascular structures. Sometimes, blue homogeneous pigmentation throughout is observed.
Lipidized dermatofibroma
Lipidized dermatofibroma usually manifests with the presence of single/multiple foci of yellow coloration/pigment.
- ↑ Zaballos et al.: Dermoscopy of dermatofibromas: a prospective morphological study of 412 cases. Arch Dermatol 2008;144:75-83. PMID: 18209171. DOI.
- ↑ Ferrari et al.: Typical and atypical dermoscopic presentations of dermatofibroma. J Eur Acad Dermatol Venereol 2013;27:1375-80. PMID: 23176079. DOI.
- ↑ Zaballos et al.: Dermoscopy of dermatofibromas: a prospective morphological study of 412 cases. Arch Dermatol 2008;144:75-83. PMID: 18209171. DOI.
- ↑ Ferrari et al.: Typical and atypical dermoscopic presentations of dermatofibroma. J Eur Acad Dermatol Venereol 2013;27:1375-80. PMID: 23176079. DOI.
