Dermatofibromas

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 Author(s): Ignacio Gómez Martín, Pedro Zaballos

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Description	This chapter describes dermoscopy of dermatofibromas
Author(s)	Ignacio Gómez Martín · Pedro Zaballos
Responsible author	Pedro Zaballos → send e-mail
Status	unknown
Status update	July 16, 2017
Status by	Ralph P. Braun

Dermatofibroma, Dermatoscopy, Dermoscopy, Df, Histiocytofibroma Dermatofibromas – cite! Dermatofibromas (message) Dermatofibromas – participate!

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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:

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.
• A 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 bright white areas 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: The most common vascular structures are 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 mamillatted surface.

Dermoscopy patterns:

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.

References: