A punch biopsy of the lesion was performed and the results were consistent with a dermatofibroma, which is a benign growth.
Dermatofibromas may manifest as a pink papule on fair-skinned individuals or a darker brown papule in patients of color. Clinically, the texture can be helpful to discern an etiology—dermatofibromas may dimple when pinched laterally, while melanocytic nevi or melanomas tend to be somewhat softer on palpation. Cutaneous sarcoma, while exceedingly rare, may be firmer and chaotic, and varied with multiple colors and topographical changes.
The dermoscopic pattern of a dermatofibroma includes central scar-like areas, a peripheral pigment network, occasional shiny white lines, and confluent circular brown macules. Other less frequent dermoscopic structures may also be seen. A prospective study of the dermoscopic morphology of 412 dermatofibromas found 10 distinct dermoscopic patterns, but also noted that 25% of the dermatofibromas exhibited an atypical pattern.1 Atypical pigment, multiple scar-like areas, and dotted vessels can occur in a dermatofibroma, as well as in a Spitz nevus, and melanoma. Thus, such findings should prompt a biopsy.
Dermatofibromas are safe to observe, but they can be surgically excised if they cause pain or cosmetic concerns.
This patient was reassured to know that the lesion would not require surgical intervention and was unlikely to enlarge or change significantly over time.
Photos and text for Photo Rounds Friday courtesy of Jonathan Karnes, MD (copyright retained). Dr. Karnes is the medical director of MDFMR Dermatology Services, Augusta, ME.