{'fraction_non_alphanumeric': 0.03009228300120369, 'fraction_numerical': 0.01083322188043333, 'mean_word_length': 5.040387722132472, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 1, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Lipid-rich carcinoma of the breast that is strongly positive for estrogen receptor: a case report and literature review

Lipid-rich carcinoma (LRC) of the breast is a rare breast cancer variant that accounts for <1% of all breast malignancies. It has been reported that LRCs are negative for estrogen receptor. Here, we report a case of LRC of the breast that was strongly positive for estrogen receptor and treated with endocrine adjuvant therapy. A 52-year-old postmenopausal female noticed a lump in her right breast by self-examination and presented to our hospital. Physical examination revealed an elastic 30 mm ×20 mm hard mass in the upper medial part of her right breast. The findings obtained using ultrasonography, mammography, and contrast-enhanced magnetic resonance imaging suggested breast cancer. Core needle biopsy resulted in the diagnosis of invasive carcinoma. The patient underwent mastectomy and sentinel lymph node biopsy. Histopathologically, the tumor cells were abundant in foamy cytoplasm. Because the presence of marked cytoplasmic lipid droplets was confirmed by Sudan IV staining and electron microscopic examination of the tumor and the lipid droplets were negative for periodic acid–Schiff staining, the tumor was diagnosed as an LRC. Immunohistochemically, estrogen and progesterone receptors of the tumor were strongly positive, human epidermal growth factor receptor type 2 was negative, and the ratio of Ki-67-positive cells was ~30%. After surgery, the patient underwent combination chemotherapy with anthracycline, cyclophosphamide, and 5-fluorouracil, followed by docetaxel. Thereafter, the pateint was treated with letrozole and has remained well for 24 months with no signs of recurrence.


Introduction
Lipid-rich carcinoma (LRC) of the breast is a rare form of breast cancer that accounts for ,1% of all breast malignancies according to the World Health Organization's classification of breast tumors 1 and is considered to be aggressive with a poor prognosis. 2 Although LRC is thought to be negative for estrogen receptors (ERs), 2,3 we recently experienced a case of breast LRC that was strongly positive for ERs. To the best of our knowledge, our case is the second report of ER-positive LRC, which was treated with endocrine therapy. Here, we report a case of LRC strongly positive for ER and review the literature. Written informed consent was obtained from the patient to use her data for publication. Approval was obtained from the ethics committee of Shinshu University, School of Medicine.

Case report
A 52-year-old postmenopausal female noticed a painless lump in her right breast on self-examination and presented to our hospital. The patient had no past or family history  Figure 1). Contrast-enhanced magnetic resonance imaging revealed an irregularly shaped mass with strong enhancement in the early phase. No intraductal spread of the tumor was detected ( Figure 2). Core needle biopsy of the tumor led to a diagnosis of invasive carcinoma. 18 F-Fluorodeoxyglucose positron emission tomography revealed no sign of distant metastasis. The patient was diagnosed as stage IIA breast cancer and underwent mastectomy and sentinel lymph node biopsy. Histopathologically, the tumor cells were abundant in foamy cytoplasm ( Figure 3A and B). Sudan IV staining ( Figure 3C) and electron microscopic examination of the tumor ( Figure 3D) demonstrated the presence of marked cytoplasmic lipid droplets, which were negative for periodic acid-Schiff (PAS) staining ( Figure 3E). Furthermore, gross cystic disease fluid protein-15 (GCDFP-15) staining ( Figure  3F) was negative in the cytoplasm of the tumor cells. On the other hand, cytokeratin (CK) 5/6 staining was weakly positive ( Figure 3G), while p53 staining was positive ( Figure 3H). Based on these findings, the tumor was diagnosed as LRC.
Immunohistochemically, ERs and progesterone receptors (PgRs) of the tumor were strongly positive ( Figure 4A and B), human epidermal growth factor receptor type 2 (HER2) was negative ( Figure 4C), and the ratio of Ki-67-positive cells was ~30% ( Figure 4D). No lymph node metastasis was detected in the axilla. Taking into consideration the high ratio of Ki-67-positive cells and aggressiveness of LRC, the patient received standard adjuvant chemotherapy of anthracycline, cyclophosphamide, and 5-fluorouracil, followed by docetaxel. Thereafter, the patient received letrozole and has remained well for 24 months with no signs of recurrence.

1643
Lipid-rich carcinoma of the breast positive for estrogen receptor is generally considered to be an aggressive phenotype of breast cancer.
Because of the rarity of LRC, the association between the subtype and clinical features of LRC has not been extensively studied. LRC cases reported in the English literature are summarized in Table 1     Abbreviations: TNM, tumor-node-metastasis; er, estrogen receptor; pgr, progesterone receptor; Her2, human epidermal growth factor receptor type 2; ND, not described; M, mastectomy; ax, axillary dissection; BCs, breastconserving surgery; sLNB, sentinel lymph node biopsy; CT, chemotherapy; eT, endocrine therapy.

Publish your work in this journal
Submit your manuscript here: http://www.dovepress.com/oncotargets-and-therapy-journal OncoTargets and Therapy is an international, peer-reviewed, open access journal focusing on the pathological basis of all cancers, potential targets for therapy and treatment protocols employed to improve the management of cancer patients. The journal also focuses on the impact of management programs and new therapeutic agents and protocols on patient perspectives such as quality of life, adherence and satisfaction. The manuscript management system is completely online and includes a very quick and fair peer-review system, which is all easy to use.  13,14 have been reported to be ER negative, and there has been a tendency for LRC to be HER2 positive and contain highly proliferative cells. Hence, the aggressiveness of LRC may be attributed to these biological features. However, the significance of Ki-67 levels in LRC has been not elucidated. Shi et al 2 reported that Ki-67 status was not associated with overall survival among 49 patients with LRC. However, more clinical data are required to elucidate the significance of Ki-67 in the prognosis of LRC. Treatment of LRC is typically performed on the basis of standard treatment protocols for breast cancer. However, considering the aggressiveness of LRC, systemic therapy should be an important part of the treatment regimen and appropriate systemic therapies according to the subtype and stage of each tumor should be administered. Shi et al 2 performed an in vitro chemosensitivity assay and found that lipid-rich tumors were sensitive to paclitaxel, carboplatin, and cisplatin. Thus, chemotherapy including paclitaxel or platinum agents may have the potential to improve the prognosis of recurrent LRC. On the other hand, because all LRCs except for two previously reported cases 13,14 have been ER negative, the effect of endocrine therapy on LRC has not been established. In the present case, endocrine therapy is expected to be effective because the tumor was strongly ER positive.

Conclusion
The present case is the second report of LRC that was positive for ER expression and treated with endocrine therapy. Although LRC is generally considered to be negative for ERs, our case suggests that a small percentage of LRCs are ER positive.