OncoTargets and Therapy (May 2021)
A Case of Phyllodes Tumor of the Breast with Mixed Liposarcoma: Case Report and Literature Review
Abstract
Mei Er Tu He Ta Mi Shi,1,* Ning Wang,1,* Qing Yao,1 Shuang-Shuang Dong,1 Xiao Feng,1 Jin Zhao,1 Hong Zou,1 Li-Juan Pang,1 Yan Qi1,2 1Department of Pathology, Shihezi University School of Medicine and the First Affiliated Hospital to Shihezi University School of Medicine, Shihezi, Xinjiang, 832002, People’s Republic of China; 2Department of Pathology, Central People’s Hospital of Zhanjiang and Zhanjiang Central Hospital, Guangdong Medical University, Zhanjiang, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yan Qi; Li-Juan PangDepartment of Pathology, Shihezi University School of Medicine and The First Affiliated Hospital to Shihezi University School of Medicine, North 2 Road, Shihezi, Xinjiang, 832002, People’s Republic of ChinaTel +86 150 09932652Email [email protected]; [email protected]: Phyllodes tumors (PTs) account for less than 1% of breast tumors, and malignant PTs account for even less. Here, we described an unusual case of malignant PT with mixed liposarcoma (myxoid liposarcoma [MLP] and pleomorphic liposarcoma [PLP]). A 52-year-old woman discovered a small lump in her left breast. Twenty years later, the lump suddenly grew within 1 month. Mammography showed space-occupying lesions of the left breast. Histologically, the tumor was characterized by hypercellular stroma covering the epithelium and protrusion of the myoepithelium into the cyst to form a lobulated structure; regions of loose mucus and hypercellular structures alternated. A region of peripheral benign fibroadenoma was also observed, and many stellate and spindle cells or signet ring-like cells were identified in loose areas. Some areas showed a characteristic thin branching vascular pattern. In the cell-rich area, adipocytes and odd megakaryocytes were observed. Atypical mitotic figures were observed in the cell-rich and mucus areas (16 mitoses/10 high-power fields [HPF] and 2 mitoses/10 HPF, respectively). In the immunohistochemical analysis, a small number of tumor cells were positive for AE1/3 and vimentin, whereas all cells were negative for cytokeratin 34βE12, E-cadherin, p63, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and S-100, ruling out the possibility of metaplastic carcinoma. Interestingly, cyclin-dependent kinase 4, mouse double minute 2 (MDM2), and p16 were strongly positive in both loose mucus and cell-rich areas. However, the fluorescence in situ hybridization test results showed that MDM2 was not amplified. Combined with morphological characteristics, these findings supported that the tumor was a mixed malignant PT with MLP and PLP. Our patient did not receive radiation therapy, and after 47 months of follow-up, no recurrence or metastasis occurred. This case report serves to expand the morphologic spectrum of mixed malignant PT with liposarcoma.Keywords: malignant phyllodes tumor, breast cancer, mixed liposarcoma
