We report the case of two elderly patients who developed an unusual striking eruption of the right chest wall, 6 and 8 weeks, respectively, after right axillary lymph-node dissection. The procedures were performed following diagnosis of cutaneous malignant melanoma with regional nodal metastases. Both procedures were complicated by the formation of a seroma, subsequently drained by needle aspiration. On histological examination of the first case, extravasated red cells were found around dilated vessels, which were confirmed by immunohistochemistry to be lymphatic vessels. The eruptions resolved spontaneously within 4–8 weeks. The cause of the eruption remains unclear, but possible reasons are bleeding into the seroma or the occurrence of a temporary lymphovascular anastomosis. To our knowledge, these are the first such cases reported in the literature.