Dermatofibroma in skin of color
A dermatofibroma is a scar-like benign tumor that is firm to palpation and often shows a dimple sign. On dermoscopy it typically shows a central hypopigmented or pink scar-like area surrounded by fine reticular network.
Dermoscopy features: [1] [2]
Classic dermoscopic features:
- Delicate pigment (reticulated) network at the periphery of the lesion.
- A central scar-like white or pink patch with or without shiny white lines
Additional dermoscopic features:
- Ring-like globules
- 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
- Rarely comedo-like openings, scale, ulceration, peripheral collarette fissures, ridges and mammillated surface.
The best description of DF in skin of color was performed in Morocco from 2015 to 2016 and included 100 cases. [3] All the patients had a dark skin phototype (Fitzpatrick scale types IV and V). A total of 14 morphological dermoscopic structures were distinguished, and 17 dermoscopic patterns were observed, with the most common pattern being the central white patch and peripheral pigment network (21%).
Examples in a variety of patients with skin of color
The arm of a 48-year-old African-American woman with a dermatofibroma.
1. Peripheral fine network – blends into surrounding darker pigmentation 2. Central white or pink scar-like area – less pink 3. Ring-like globules – annular edge is less visible
African-American woman - leg
Central shiny white structures that are creating polygonal patterns (not one of typical 10 patterns described by Zaballos et al.)[1]
31yo Indian man – arm -clear ringlike globules with white scar like center and particular network fine on the edge
African-American woman leg
Note the barely visible short shiny white lines in the center
DF in a 53 yo Chinese man
26-year-old Hispanic female – note how the ring globules have more visible ring edges with the lighter skin - Fitzpatrick IV
Never forget to do the pinch test:
Pinch test of a DF on the abdomen
DF with visible vessels and more keratin on the surface than usual. Central white lines/scar are typical.
Links to additional chapters on Skin of Color
References
- ↑ 1.0 1.1 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.
- ↑ Kelati et al.: Beyond classic dermoscopic patterns of dermatofibromas: a prospective research study. J Med Case Rep 2017;11:266. PMID: 28927449. DOI.
