The Stewart-Treves syndrome is a rare and deadly entity, which is defined as angiosarcoma arising in the setting of chronic lymphedema. It typically presents in women who develop lymphedema in the upper extremity secondary to axillary lymph node dissection for breast cancer surgery. It is extremely uncommon in the lower extremities as a result of idiopathic chronic lymphedema. Here, we present the case of a 63-year-old female patient with idiopathic chronic lymphedema of the lower extremities having morbid obesity (BMI 82.6) and multiple comorbidities. She developed multiple confluent, hemorrhagic and necrotic elevated purple-black papules in the lower extremities, for which the initial diagnosis was cellulitis. Because there was no improvement with antibiotics, a lower extremity ultrasound and biopsy was performed which showed multiple masses in the left inner upper calf with solid and cystic components. The pathology results of the punch biopsies were consistent with angiosarcoma. Immunohistochemical studies revealed positivity for CD31, FLI-1, and a high Ki-67 proliferation rate. Because of the patient's weight and medical comorbidities, no further extensive diagnostic tests were performed to detect metastatic disease, and because of contraindications, no further medical treatment was provided. The patient subsequently died 1 month after diagnosis.