title: Lipid-rich carcinoma of the breast that is strongly positive for estrogen receptor: a case report and literature review.
abstract: 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.
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Oba
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Ono
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Asumi
authors.initials: A
authors.lastname: Iesato
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hanamura
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Tokiko
authors.initials: T
authors.lastname: Ito
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Kanai
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Maeno
authors.affiliation: Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Ito
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Tateishi
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshizawa
authors.affiliation: Imaging Center, Ichinose Neurosurgical Hospital, Matsumoto, Japan.
authors.forename: Fumiyoshi
authors.initials: F
authors.lastname: Takayama
keywords: breast cancer; endocrine therapy; estrogen receptor