Case Presentation
A 48-year-old otherwise healthy Caucasian woman presented with two weeks history of a painless lump in the right breast. There was neither history of trauma nor chest wall irradiation, nor a previous history of a benign or malignant lesion in the breast. No screening mammography had been performed by that time. Physical examination revealed an ill-defined, firm, mobile, and nontender six cm mass in the central and lateral portion of the breast, behind the nipple-areola complex.
The physical exam of the axillary area and contralateral breast were unremarkable.
The mammography and ultrasonography revealed an irregular bulky mass with a lobulated border in the lateral part of the right breast. On MRI study, there was a 4 cm mass in the lateral part of the right breast with a high signal intensity at the periphery of the tumor.
The initial Core needle biopsy findings were compatible with extra-skeletal osteosarcoma which was confirmed by the second opinion based on the exclusion of the phyllodes tumor and metaplastic carcinoma along with performing IHC that was strongly positive for vimentin with 30-35% proliferative activity (Ki 67) and nonreactive for Pan-Ck.
There was no evidence of distant metastasis based on liver function test, chest and abdominal CT, and bone scan.
As our institute routine, the patient was discussed in a multidisciplinary team and a simple mastectomy followed by Adriamycin and Ifosfamide regimen of chemotherapy and 50 Gy radiation was planned for her.
The patient underwent a simple mastectomy. Although the tumor was not grossly fixed to the underlying chest wall structures, the deep margin was too close to the fascia of the pectoralis muscle. Therefore, a thin discoid shape layer of pectoral muscle just beneath the tumor lodge was resected en-bloc with the rest of the specimen. Additionally, four enlarged lymph nodes were resected as a caution. All parts of the specimen were sectioned into 4 μm thick and were stained with hematoxylin and eosin as well as Elastica van Gieson. Histological evaluation of the surgical specimen showed atypical tumor cells that were embedded in extensive ossified vermiform plexus of osteoid, bearing necrosis, and autolysis. There was no chondroid differentiation nor evidence of phyllodes tumor or metaplastic carcinoma. The histological result was confirmed by IHC with the avidin-biotin-peroxidase complex method leading to negativity for Pan-CK and CAM 5.2 as well as strong positivity for Vimentin in addition to 30-35% proliferative activity (Ki67). All margins and lymph nodes were free of tumor. It is worth mentioning that all the histological evaluations have been done by two expert pathologists in the field of sarcoma separately.
After recovery, the patient underwent chemotherapy with the mentioned regimen for five cycles and subsequently received radiotherapy 50 Gy. The treatment plan finished uneventfully last month.