Ultrastructurally confirmed myofibrosarcoma: a series of 10 new cases, with a discussion on diagnostic criteria

Myofibroblastic sarcoma in breast: a case report and literature review

Myofibroblastic sarcoma is a malignancy in which myofibroblasts are the main component, with a very low incidence. In this study, we report a case of low-grade myofibroblastic sarcoma (LGMS) in the breast. After the diagnosis of LGMS, the patient received a mastectomy. The patient showed no relapse or progression during the follow-up time of 3 months following the operation. LGMS in the breast is extremely rare, and the limited experience with its diagnosis and treatment brings obstacles to doctors. Therefore, this report summarizes the preoperative diagnosis, treatment, and prognosis of breast LGMS through a literature review.

Myofibroblastic sarcoma of the breast. Report of a case induced by radiotherapys

Myofibroblastic sarcoma (MFS) is an uncommon tumor rarely located in the breast. Ionizing radiation is a carcinogen capable of inducing sarcomas through DNA damage. A 42-year-old woman was diagnosed with synchronous bilateral breast infiltrating ductal carcinoma with axillary lymph node metastases on the left side. After modified left radical mastectomy and simple right mastectomy, she underwent postoperative radiation with a total volume dose of 50 Gy that included the thoracic wall and the left axillary-supraclavicular region. After a latency period of 6 years and 4 months, the patient developed an MFS in the area of radiation (mammary upper outer quadrant). To our knowledge, only 11 cases of MFS have been previously published in the breast. The study of the 12 cases including the present one revealed that the ages of the patients ranged from 42 to 86 years (mean 60.3 years). There was a clear difference concerning sex (M:F, 1:5). The average duration of the lesion varied from 1 week to 8 months (mean 3.3 months). The size ranged from 2.2 to 22 cm (average 5.1 cm). The tumors showed frequent mitosis and areas of necrosis. The percentage of recurrences, metastasis, and death due to the tumor was 27.3%, 36.4%, and 27.3% respectively. MFS cases differ from those affecting extramammary regions. They are more common in females and show a greater degree of aggressiveness. Correct diagnosis of mammary MFS requires morphological and immunohistochemical study. We present for the first time a case of MFS of the breast induced by radiotherapy.

Myofibroblastic, fibroblastic and myoid lesions of the breast

Myofibroblastic, fibroblastic and/or myoid lesions are rare in the breast but comprise the majority of mammary mesenchymal spindle cell lesions. Whereas most have similar features to their counterparts at extramammary sites, pseudoangiomatous stromal hyperplasia is considered a breast-specific myofibroblastic proliferation on the same spectrum as myofibroblastoma. Other lesions with myofibroblastic/fibroblastic differentiation include fibromatosis and nodular fasciitis, as well as more aggressive tumors such as the rarely reported myofibrosarcoma, inflammatory myofibroblastic tumor and fibrosarcoma. Lesions with myoid differentiation include benign leiomyoma, myoid hamartoma and leiomyomatous myofibroblastoma, but primary leiomyosarcoma and rhabdomyosarcoma may also rarely arise in the breast. Furthermore, fibroepithelial lesions and metaplastic carcinomas can demonstrate myoid metaplasia. Diagnosis can be challenging, particularly on core biopsy, but benign lesions with or without recurrence potential must be distinguished from more aggressive tumors, especially metaplastic carcinoma and phyllodes tumors. This article will review lesions with myofibroblastic, fibroblastic and myoid differentiation in the breast, with special emphasis on differential diagnosis.