Chronic lymphedema-associated angiosarcomas, also known as Stewart-Treves syndrome, are a very rare subtype of angiosarcoma. Angiosarcomas are the most common tumor associated with chronic lymphedema ¹².

Terminology

Chronic lymphedema-associated angiosarcoma is used in the WHO Soft Tissue and Bone Tumors (5th ed.); lymphangiosarcoma is not a recommended term ⁵.

Epidemiology

These tumors affect females more than males, as it is commonly associated with post-mastectomy lymphedema. The incidence is unknown, but studies have shown that it has occurred in ~0.25% (range 0.03-0.45%) of patients who survive at least 5 years after radical mastectomy ^6,7.

The mean duration of lymphedema before diagnosis is ~11 years (range 1-50 years) in patients with a history of cancer and ~25 years (range 0.5-85 years) in patients without a history of cancer ¹².

Clinical presentation

Chronic lymphedema with skin and soft tissue tumor in the involved limb. A history of previous radical mastectomy for breast cancer is supportive in cases of upper limb lymphangiosarcoma.

Pathology

Chronic lymphedema-associated angiosarcomas was first associated with lymphedema secondary to radical mastectomy to treat breast cancer ¹³; however, it has been shown to arise in chronically lymphedematous regions of any cause ⁸. Chronic lymphedema seems to induce a degree of local immunodeficiency that leads to oncogenesis ⁹.

Distant metastasis occurs in ~15% of patients ¹², most commonly of the lung, lymph nodes, soft tissues, bone, and liver ⁵.

Etiology

It can arise from any cause of chronic lymphedema:

• mastectomy-induced lymphedema ^10,11

• post axillary dissection and/or radiation therapy ¹²

• Milroy disease ^10,11

• congenital lymphedema ^10,11

• traumatic lymphedema ^10,11

• filarial lymphedema ^10,11

• elephantiasis nostras verrucosa ^10,11

• idiopathic lymphedema ^10,11

Radiographic features

Often, it is radiologically difficult to identify the extent of the tumor ^ref.

MRI

MRi demonstrates an enhancing vascular nodular soft tissue mass, which involves soft tissue and skin of the involved limbs and is associated with findings subcutaneous tissue edema ^ref.

Signal characteristics

• T1: intermediate signal

• T2: low signal

• T1 C+ (Gd): high signal ^ref

Nuclear medicine

The tumor shows avid uptake on PET-CT ^ref.

Treatment and prognosis

This is a poor prognostic tumor, the mean survival rate is ~ 2 years with a 5-year survival rate of ~20% ¹². The treatment is aggressive surgical resection and amputation of limbs is frequently recommended, even though the recurrence rate still high ^ref.

History and etymology

The occurence of angiosarcoma in patients with chronic lymphedema post radical mastectomy was first reported by American pathologist FW Stewart (1894-1991) and American surgeon N Treves (d. 1964) in 1948 ^13-15.