Breast Mucinous Cystadenocarcinoma in A 69-Year-Old Female with ER, PR Positivity : A Case Report

Mucinous cystadenocarcinoma (MCA) is a relatively rare histological subtype of breast cancer.(1) It is composed of multiple cysts with more than 50% mucinous components.(2, 3) Mucinous cystadenocarcinoma of the breast presents as a lobulated gelatin-like and well-circumscribed mass on mammography, sonography , and magnetic resonance imaging. It is associated with a good prognosis due to the low incidence of axillary lymph node involvement and infiltration of overlying skin. Short-term prognosis is excellent especially when the tumor measures <5 cm in diameter on gross. Mucinous cystadenocarcinoma usually occurs in elderly and the median age at diagnosis is older than 55-60 years. The incidence of MCA reported to be 1-6% of all primary breast cancers.(2, 4) On immunohistochemical stain, estrogen receptor(ER), progesterone receptor (PR) and HER2 are negative.(5-7) Here, we report a rare case of MCA of left breast in a 69-year-old female which has a different IHC report. Case presentation A 69-year-old female referred to clinic with chief complaint of a painful lump in her left breast from 3 months ago. She also complained of bloody discharge from left nipple since four years ago. Despite recommendations for diagnostic procedure, the patient decided not to follow up. In physical examination, an erythematous tender mass, owning hard consistency on palpation was detected around nipple led to further radiological investigations. Sonography showed two lobulated hypoecho masses with microcyctic areas measuring 30×17 mm and 14.8×9.4 mm at 3o’clock beside areol (Fig 1). Mamography also showed a hyperdense mass in retroareolar site. The patient admitted and underwent surgery. According to intraoperative pathology consultation based on multiple frozen sections from the mass, left modified radical mastectomy and lymph node dissection is done. Conclusions:Mucinous cystadenocarcinoma of the breast is extremely rare entity which has a higher incidence in peri- and post-menopausal women. (8)Mucinous carcinoma typically appears in two different subtypes, the cystic (mucinous cystadenocarcinoma) and solid (columnar cell mucinous carcinoma)(9). Microscopically, the tumors were characterized by cystic spaces lined by predominantly bland-appearing columnar mucinous cells with stratification and papillary formations. Varying degrees of cytologic atypia were focally evident, with gradual loss of the intracytoplasmic mucin and transformation to an eosinophilic squamoid cell population.(10) On immunohistochemical stain, estrogen receptor (ER), progesterone receptor (PR), Her2neu were negative.(5, 6). We present the case of a mucinous cystadenocarcinoma of the breast in addition to the characteristic immunophenotype ER(+), PR(+) and Her2(-).In comparison to intraductal carcinoma-NOS Less chemotherapy and more hormone therapy were applied to Pure Mucinous carcinoma patients, probably because of the favorable features associated with higher ER or PR expression and lower histologic grade in MCA. Although mucinous cyst adenocarcinomas are mostly negative for ER and PR.(2)In our case because of positivity of hormone receptors which is so rare, hormonal therapy can be beneficial for the patient. Because of low incidence of lymph node involvement , mucinous cystadenocarcinoma has a relatively good prognosis.(6) Despite the relatively enormous size of the tumor, the margins are free and no lymph node metastasis is identified hence rendering favourable prognosis. Careful clinical and radiologic correlation and a review of patient’s prior medical history are needed to rule out metastasis from ovarian,pancreas or colorectal mucinous carcinoma, although the breast is the rarest area for metastasis from these regions.(11)Mucinous cystadenocarcinoma of breast typically is Triple negative for hormonal receptors. It is important to know that rare variant with positivity for ER and PR is exist to be aware of differente therapy and prognosis. Hormonal therapy for this patients is beneficial and prognosis is more favorable.

کلیدواژه ها:

Breast Cancer ، Mucinous cystadenocarcinoma ، Estrogen receptor ، Progesterone receptor