Acquired digital arteriovenous malformation of the toe showing tendency to clinically regress after skin biopsy: A case report

Introduction: Acquired digital arteriovenous malformation (ADAVM) is a rare vascular anomaly characterized by direct arteriovenous shunts, typically occurring on the digits and often associated with trauma. Toe-localized ADAVM is particularly uncommon. Case Presentation: A 65-year-old man presented with a persistent dark purple macule on the dorsal aspect of the right fifth toe for over three years. Dermoscopy showed hairpin vessels with a white halo. Histopathological examination revealed epidermal hyperplasia, parakeratosis, elongation of rete ridges, and dilated vascular structures composed of capillaries, veins, and arterioles extending from the subepidermal dermis into the dermal papillae. Based on these findings, the patient was diagnosed with ADAVM. Following diagnostic skin biopsy, the lesion regressed without any additional intervention. Conclusion: We report a rare case of toe-localized ADAVM showing regression after skin biopsy. This case suggests that biopsy-related alterations in local hemodynamics may contribute to lesion regression and highlights the importance of considering ADAVM in the differential diagnosis of persistent dark red macules on the digits.