Radiation-induced undifferentiated pleomorphic sarcoma of the breast

Abstract

Breast sarcoma is a rare form of malignancy that arises from connective tissue within the breast, comprising less than 5% of all sarcomas. They develop as primary tumours or as secondary following radiation therapy. Diagnosis can be challenging as breast sarcomas are often asymptomatic and resemble benign breast tissue changes. Radiation-induced breast sarcomas present in various forms with an average latency period of 10–20 years following initial radiation therapy. Angiosarcomas are the most common form, while other types such as undifferentiated pleomorphic sarcomas remain rare. Here, we report a case of radiation-induced undifferentiated pleomorphic breast sarcoma in a 75-year-old woman that developed nearly 20 years following breast conserving surgery and radiation for invasive ductal carcinoma. The patient initially noticed a mass in 2017 on self-examination. The mammogram, ultrasound and biopsy at the time showed a benign 2.2 cm nodular fasciitis without malignancy. The mass grew rapidly in the next 6 months to 5.6 cm and repeat biopsy diagnosed undifferentiated pleomorphic sarcoma. The mass abutted the pectoralis muscle but staging workup ruled out distant metastasis and the patient underwent wide local resection of the mass with clear margins. The patient subsequently underwent further postoperative radiation due to insufficient posterior margin width on wide local excision, as chest wall resection would have been required for a wider posterior margin. Prognosis for postradiation sarcomas is generally poor with 27%–36% 5-year survival, with surgical resection as the main line of treatment. The patient currently remains disease-free after 15 months of surveillance.

Radiation-Induced Undifferentiated Pleomorphic Sarcoma after Breast Conserving Therapy: Case Report

“…The prognosis for post radiation sarcomas is generally poor, with a 5-year survival rate of 27%-36% and has a high local rate of recurrence and metastasis 3 . Surgical intervention is a standard treatment for individuals who have not yet developed distant metastasis, and complete resection is crucial for a favorable long-term prognosis.…”

“…Chemotherapy may not be very effective but tend to be prescribed in similar patients and in unresectable tumors. Therefore, the best treatment plan for each patient should be determined through a multidisciplinary approach, as there is no standard treatment protocol but a decision considering known prognostic factors and the surgery's outcome 3 .…”

“…Breast sarcomas can occur as a primary tumor and as a secondary form associated with a history of radiation therapy. Some authors 6 describe UPS as the most common histopathological type 6 , others as angiosarcomas 3,7 ; nevertheless, sarcomas following irradiation of breast cancer are rare and cumulative incidence is about 0.2% in 10 years 8 . They occur predominantly in 45-50 years old patients 9 .…”

“…Diagnosis radiation-induced UPS can be challenging, first because the tumor is usually asymptomatic, and second, the post-radiation aspect of the breast tissue turns physical examination less sensitive 3 . Breast sarcomas most commonly manifest as a large, painless, mobile mass (mean diameter of 3 cm, reaching up to 30 cm), with rapid enlarging.…”

“…Breast sarcoma is a rare group of heterogeneous nonepithelial tumors that appear in the connective tissue within the breast and are associated with poor prognosis. Subtypes include angiosarcoma, leiomyosarcoma, liposarcoma, fibrosarcoma and undifferentiated pleomorphic sarcoma (UPS), formerly known as malignant fibrous histiocytoma 3,4 . The present case describes a UPS secondary to RT for breast cancer with discussion of diagnosis and management challenges.…”