Radiation-induced low-grade fibromyxoid sarcoma of the chest wall nine years subsequent to radiotherapy for breast carcinoma: A case report.

The present study reports a case of low-grade fibromyxoid sarcoma that occurred in a 62-year-old woman 9 years subsequent to whole breast irradiation for a carcinoma of the left breast, and 18 years following chemotherapy and radiotherapy (RT) for non-Hodgkin's lymphoma (NHL; diagnosed at the age of 43). The patient was 53 years of age when a cT2N0M0 stage IIA breast tumor was identified and excised. A 2.5 cm diameter nodule with dimpling in the upper-outer region of the left breast was detected. Pathological examination revealed that the tumor was an invasive ductal carcinoma, of a solid tubular type. The patient was treated with post-surgical whole breast RT. The left breast received 46 Gy in 23 fractions (2 Gy per fraction) for 4 weeks and 3 days, followed by a cone down boost of 14 Gy in 7 fractions (2 Gy per fraction); therefore a total dose of 60 Gy in 30 fractions was administered. In total, 9 years subsequent to RT, the patient observed a small lump in the left chest wall. The patient underwent excision of the tumor and pectoralis major fascia. Microscopically, the tumor consisted of atypical spindle cells with myxoid stroma. Pathologists concluded that the tumor was a low-grade fibromyxoid sarcoma. Since the tumor developed from tissue in a previously irradiated region, it was considered to be RT-induced, and was classified using the radiation-induced sarcoma (RIS) criteria as dictated by Cahan. Although the majority of RIS cases are angiosarcomas, a rare, low-grade fibromyxoid sarcoma was observed in the present study. The present study hypothesizes that there may have been an overlap region between the RT for supraclavicular nodes of NHL and the whole breast RT for primary breast cancer, due to the results of a retrospective dose reconstruction undertaken by the present study. The patient remained clinically stable for 4 years thereafter, until 2008 when the patient experienced a local relapse and underwent surgery. On 19 October 2011, the patient succumbed to RIS. The current study suggests that the RT history of a patient requires consideration due to the possible development of RIS, including the development of a low-grade fibromyxoid sarcoma, which may lead to a poor prognosis.