RESUMEN
Breast carcinoma arising from a fibroadenoma is an uncommon entity and is frequently detected incidentally during pathological examination or excisional biopsy of a benign breast tumor. Due to only sporadic cases being reported, evidence-based guidelines are not well-established to date. The present report describes 16 patients diagnosed with breast carcinoma arising within a fibroadenoma in the Third Hospital of Nanchang (Nanchang, China) between January 2019 and December 2021 and discusses the clinicopathological characteristics, imaging findings and treatment. The age of patients at diagnosis ranged between 19 and 58 years and a well-defined asymptomatic mass was the most common clinical presentation. Carcinoma occurring in fibroadenoma generally mimics a benign tumor and potential carcinomatous changes may not be detected. Pathologically, carcinoma in situ was the predominant subtype in the present study. Additionally, ductal carcinoma in situ was more common compared with lobular carcinoma in situ in the present case series. Regarding the molecular phenotypes, the majority of cases were categorized as luminal subtype, although other subtypes such as triple-negative and HER2 positive breast cancer were also identified. In the present study, seven patients were treated with breast-conserving surgery and nine patients were treated with mastectomy. Sentinel lymph node biopsy was performed in all patients and none exhibited axillary node metastasis. Additionally, six patients underwent radiotherapy and two received chemotherapy. During the follow-up, all patients were alive and no evidence of disease relapse was observed. In summary, clinicians should be aware of the possibility of carcinoma within a fibroadenoma, which could alter the therapeutical course. Adequate biopsy or excision should be performed in patients with indicators of malignant transformation in a presumed benign breast tumor.
RESUMEN
BACKGROUND: Breast carcinoma arising in a benign fibroepithelial tumor is rare, and is usually discovered incidentally during examination of the breast mass. METHODS: We evaluated the clinicopathological features, treatment, and prognosis of seven women with breast carcinomas within benign fibroepithelial tumors, diagnosed and treated at a single institution between 2011 and 2015. RESULTS: Seven women, aged 21-64 years, visited our hospital complaining of a breast mass detected by self-checking or screening examination. All patients had well-demarcated movable breast masses. Ultrasonography showed circumscribed masses suggesting benign tumors in all cases, and mammography revealed well-defined, high-density masses, with or without calcification. The masses progressed in two patients. A preoperative histological diagnosis of carcinoma was made following needle biopsy in four patients. Tumorectomy, breast-conserving surgery, and mastectomy were performed in three, two, and two patients, respectively. One patient underwent lymph node dissection and another underwent sentinel node biopsy. Histologically, the masses were diagnosed as invasive ductal carcinoma, ductal carcinoma in situ or lobular carcinoma in situ, arising in a benign phyllodes tumor, fibroadenoma, or fibroadenomatoid mastopathy. Lymph node metastasis was detected in two patients. There was no recurrence in any of the patients. CONCLUSIONS: Although a carcinoma within a preexisting benign fibroepithelial tumor is extremely rare, it is important to be aware of the possibility of invasive and metastatic disease.