Aneurysmal Dermatofibroma After Varicose Vein Surgery

Case presentation

A 45-year-old man was referred to dermatology consultations for evaluation of a pigmented lesion on the left leg. The lesion appeared at the incision site of a varicose vein surgery performed one year prior.

Clinical examination revealed an indurated 12 mm brown plaque (Figure 1A). Dermoscopy showed at the center white network surrounded by bluish areas and a rainbow pattern, and at the periphery a homogeneous brown color (Figure 1B). Histopathological examination revealed blood-filled spaces with peripheral hemosiderin deposits, and a dense collagenous stroma containing spindle cells (Figure 1C). Immunohistochemical tinctions for Factor XIIIa (Figure 1D) and for CD68 were positive, while human herpesvirus 8 was not detected.

Figure 1.

(A) Clinical examination of the lower limbs. The hematoma on the right leg is unrelated to the reason for consultation. (B) Multi-component dermoscopic pattern composed of central white stripes with rainbow areas, and a peripheral brown network. (C) Dense tumoral stroma with congested blood vessels; the epidermis shows basal layer hyperpigmentation, acanthosis and hyperkeratosis. (D) diffuse positivity for factor XIIIa throughout the tumor.

Teaching point

Aneurysmatic dermatofibroma represents approximately 1.7% of all types of dermatofibromas [1]. Like any dermatofibroma, this subtype may appear after local trauma. Its clinical diagnosis can be difficult due to its resemblance to malignant tumors, such as Kaposi sarcoma, angiomatoid malignant fibrous histiocytoma and melanoma [2].