Cutaneous angiosarcomas of the scalp are rare and aggressive tumors with non-specific appearances. They rarely affect the retroauricular region, and diagnoses are often difficult and delayed. We present the case of an 87-year-old patient referred for a large, spontaneously appearing, and rapidly progressing retroauricular bruise while on anticoagulants. Initial biopsies were negative, and the cervico-facial computed tomography (CT) scan with contrast injection was inconclusive. Despite stopping the anticoagulants, the lesion persisted and extended, leading to new biopsies that revealed a high-grade cutaneous angiosarcoma. Positron emission tomography-computed tomography (PET-CT) detected homolateral supraclavicular lymph node involvement and pleuropulmonary metastases. Given the patient's deteriorating general condition and the metastatic spread of the disease, exclusive comfort care was decided. With a highly variable clinical presentation, the diagnosis of cutaneous angiosarcoma is often delayed and made at a metastatic stage. Optimal treatment remains complete surgical excision followed by radiotherapy, but this is challenging in very extensive tumors.